{"id":3235,"date":"2010-12-29T11:14:24","date_gmt":"2010-12-29T10:14:24","guid":{"rendered":"http:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3235"},"modified":"2019-10-05T14:29:01","modified_gmt":"2019-10-05T13:29:01","slug":"the-handedness-of-dna-an-unheralded-connection","status":"publish","type":"post","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3235","title":{"rendered":"The handedness of DNA: an unheralded connection."},"content":{"rendered":"
\n

Science is about making connections. Plenty are on show in Watson and Crick’s famous 1953 article on the structure of DNA[1]<\/a><\/span> but often with the tersest of explanations. Take for example their statement “Both chains follow right-handed helices<\/em>“. Where did that come from? This post will explore the subtle implications of that remark (and how in one aspect they did not quite get it right!).<\/p>\n

The right handed helix is illustrated in the article cited above as perhaps the most famous scientific diagram of the 20th century<\/a> (as recounted in the TV program by Marcus du Sautoy).\u00a0It was drawn by Odile Crick, a professional artist, and it is easily her best known work (the original, sadly, appears lost). Many say it has never been bettered; I do not reproduce it here for fear of copyright infringement, but you can see Odile (who died only recently) and her diagram here<\/a>. One however has to go to the Watson-Crick (WC) full paper[2]<\/a><\/span> for an explanation of why they decided the helix was right-handed, or (P)- in CIP terminology.[3]<\/a><\/span> In my opinion (as a chemist), this is a far better read than the short and more famous note in Nature. There (on page 87) one finds the immortal statement “we find by trial and error that the model can only be built in a right-handed sense”<\/em>. They follow that remark with another which I will quote later in this post. But the preceding observation is footnoted, and that footnote must rank as one of the most unheralded in science (unlike e.g.<\/em> Fermat’s). For this footnote notes another article, published just two years earlier[4]<\/a><\/span> in which the absolute handedness of a small molecule was finally confirmed after ~50 years. The molecule is shown below, and again in modern CIP terminology, the two chiral carbon atoms both have (R) configurations rather than (S). Until this point, the (R) configuration had merely been a guess with an evens chance of it being right (and had it been wrong, imagine how many textbook diagrams would have needed changing!).<\/p>\n

\"\"<\/a>

The absolute configuration of natural tartaric acid.<\/p><\/div>\n

Chemists had, in the preceding 50 years, by synthesis and transformation, connected the configuration of tartrate to the ribose sugars that form the linker in DNA, and so Watson and Crick built their famous model of DNA assured in the knowledge that the absolute configuration<\/strong> of their ribose sugar was correct. But that assurance, it is important to remember, had only come two years earlier! The (correct) structure of DNA was very much a discovery of its time, and this connection between tartrate and DNA I think deserves the accolade of great connections in science <\/em>(I write this in the Semantic Web sense).<\/em><\/p>\n

On to another statement to be found in the full WC article: “Left handed helices can only be constructed by violating the permissible van der Waals contacts<\/em>” Given the nature of the molecular model building tools that WC[5]<\/a><\/span> had at their disposal,*<\/sup> I suspect we must forgive them this assertion.[6]<\/a><\/span>,[7]<\/a><\/span> But of course, building models using the van der Waals<\/a> constraints (amongst others of course) is what modern computers are really very good at. So what might a modern visitation of this very issue yield? Shown below is a small DNA duplex, named d(CGCG)2<\/sub> (DOI: 10.2210\/pdb1zna\/pdb<\/a>)\u00a0This uses only the CG base-pairing motif (the other of course is AT). Well, it turns out that DNA constructed from CG-rich duplexes does NOT necessarily adopt a right handed helix after all! WC (for this particular condition) were in fact wrong, and clearly the van der Waals contacts are not after all objectionable. Left-handed helices (as a left hander myself, I am naturally drawn to them) are also known as Z-DNA (the right handed form is called B-DNA), although many left-handed representations have in fact been drawn in error<\/a>.<\/p>\n


\n\"\"

The DNA duplex d(CGCG) showing a left handed helix. The ribose is in the 2E conformation. Click for 3D and see if you can find any objectionable van der Waals contacts!<\/p><\/div>\n

\nThe model when stripped of its water molecules, is then of a size (250 atoms) which is easily amenable to a modern quantum-mechanical DFT calculation. Importantly, this has to include dispersion corrections (the van der Waals contacts referred to above) to get the correct geometry, and one can use e.g.<\/em> \u03c9B97XD\/6-31G(d) + continuum water solvation correction to compensate for the missing waters[8]<\/a><\/span> for an example of its use for a large molecule, or indeed this post<\/a>). In truth, this combination of characteristics in a model has only recently become possible for a molecule of such size.<\/p>\n

Well, now that a good accuracy wavefunction for e.g.<\/em> d(CGCG) is possible, what might one do with it? Well, the chiro-optical properties might be calculated[9]<\/a><\/span> including the optical rotation at a specified frequency<\/a>, or e.g.<\/em> the electronic circular dichroism spectrum. Such properties are normally computed only for much smaller molecules. Watch this space (or the journals).<\/p>\n

\n

* <\/sup>Note added in proof (as the saying goes): This article[5]<\/a><\/span> by Derek Barton published in 1947, some six years before WC claimed “violation of \u00a0the permissible van der Waals contacts<\/em>“, established clearly the principles behind the model building by WC and in many ways could be described as the start of quantitative molecular model building. The very same equation used by Barton to model dispersion attractions is still used in e.g.<\/em> the \u03c9B97XD DFT method noted above.<\/p>\n

References<\/h2>\n
  1. J.D. WATSON, and F.H.C. CRICK, \"Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid\", Nature<\/i>, vol. 171, pp. 737-738, 1953. https:\/\/doi.org\/10.1038\/171737a0<\/a>\n\n<\/li>\n
  2. F.H.C. Crick, and J.D. Watson, \"The complementary structure of deoxyribonucleic acid\", Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences<\/i>, vol. 223, pp. 80-96, 1954. https:\/\/doi.org\/10.1098\/rspa.1954.0101<\/a>\n\n<\/li>\n
  3. R.S. Cahn, C. Ingold, and V. Prelog, \"Specification of Molecular Chirality\", Angewandte Chemie International Edition in English<\/i>, vol. 5, pp. 385-415, 1966. https:\/\/doi.org\/10.1002\/anie.196603851<\/a>\n\n<\/li>\n
  4. J.M. BIJVOET, A.F. PEERDEMAN, and A.J. van BOMMEL, \"Determination of the Absolute Configuration of Optically Active Compounds by Means of X-Rays\", Nature<\/i>, vol. 168, pp. 271-272, 1951. https:\/\/doi.org\/10.1038\/168271a0<\/a>\n\n<\/li>\n
  5. D.H.R. Barton, \"83. Interactions between non-bonded atoms, and the structure of cis-decalin\", Journal of the Chemical Society (Resumed)<\/i>, pp. 340, 1948. https:\/\/doi.org\/10.1039\/jr9480000340<\/a>\n\n<\/li>\n
  6. F. Crick, J.C. Wang, and W.R. Bauer, \"Is DNA really a double helix?\", Journal of Molecular Biology<\/i>, vol. 129, pp. 449-461, 1979. https:\/\/doi.org\/10.1016\/0022-2836(79)90506-0<\/a>\n\n<\/li>\n
  7. R. Wing, H. Drew, T. Takano, C. Broka, S. Tanaka, K. Itakura, and R.E. Dickerson, \"Crystal structure analysis of a complete turn of B-DNA\", Nature<\/i>, vol. 287, pp. 755-758, 1980. https:\/\/doi.org\/10.1038\/287755a0<\/a>\n\n<\/li>\n
  8. H.S. Rzepa, \"Can 1,3-dimethylcyclobutadiene and carbon dioxide co-exist inside a supramolecular cavity?\", Chem. Commun.<\/i>, vol. 47, pp. 1851-1853, 2011. https:\/\/doi.org\/10.1039\/c0cc04023a<\/a>\n\n<\/li>\n
  9. S. Ding, A. Kolbanovskiy, A. Durandin, C. Crean, V. Shafirovich, S. Broyde, and N.E. Geacintov, \"Absolute configurations of DNA lesions determined by comparisons of experimental ECD and ORD spectra with DFT calculations\", Chirality<\/i>, vol. 21, 2009. https:\/\/doi.org\/10.1002\/chir.20804<\/a>\n\n<\/li>\n<\/ol>\n\n<\/div> ","protected":false},"excerpt":{"rendered":"

    Science is about making connections. Plenty are on show in Watson and Crick’s famous 1953 article on the structure of DNA but often with the tersest of explanations. Take for example their statement “Both chains follow right-handed helices“. Where did that come from? This post will explore the subtle implications of that remark (and how […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"activitypub_content_warning":"","activitypub_content_visibility":"","activitypub_max_image_attachments":5,"activitypub_interaction_policy_quote":"anyone","activitypub_status":"","footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[4],"tags":[384,224,575,381,46,380,374,2651,385,393,375,376,383,379,572,382,377,378],"ppma_author":[2661],"class_list":["post-3235","post","type-post","status-publish","format-standard","hentry","category-interesting-chemistry","tag-bijvoet","tag-chemist","tag-chiroptical","tag-dcgcg","tag-derek-barton","tag-dispersion-forces","tag-dna-duplex","tag-historical","tag-marcus-du-sautoy","tag-note","tag-odile-crick","tag-professional-artist","tag-tartaric-acid","tag-van-der-waals","tag-watoc11","tag-watson-crick","tag-web-sense","tag-z-dna"],"yoast_head":"\nThe handedness of DNA: an unheralded connection. - Henry Rzepa's Blog<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3235\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"The handedness of DNA: an unheralded connection. - Henry Rzepa's Blog\" \/>\n<meta property=\"og:description\" content=\"Science is about making connections. Plenty are on show in Watson and Crick’s famous 1953 article on the structure of DNA but often with the tersest of explanations. Take for example their statement “Both chains follow right-handed helices“. Where did that come from? This post will explore the subtle implications of that remark (and how […]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3235\" \/>\n<meta property=\"og:site_name\" content=\"Henry Rzepa's Blog\" \/>\n<meta property=\"article:published_time\" content=\"2010-12-29T10:14:24+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2019-10-05T13:29:01+00:00\" \/>\n<meta property=\"og:image\" content=\"http:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2010\/12\/tartrate.jpg\" \/>\n<meta name=\"author\" content=\"Henry Rzepa\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Henry Rzepa\" \/>\n\t<meta name=\"twitter:label2\" content=\"Estimated reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"5 minutes\" \/>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"The handedness of DNA: an unheralded connection. - Henry Rzepa's Blog","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3235","og_locale":"en_GB","og_type":"article","og_title":"The handedness of DNA: an unheralded connection. - Henry Rzepa's Blog","og_description":"Science is about making connections. Plenty are on show in Watson and Crick’s famous 1953 article on the structure of DNA but often with the tersest of explanations. Take for example their statement “Both chains follow right-handed helices“. Where did that come from? This post will explore the subtle implications of that remark (and how […]","og_url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3235","og_site_name":"Henry Rzepa's Blog","article_published_time":"2010-12-29T10:14:24+00:00","article_modified_time":"2019-10-05T13:29:01+00:00","og_image":[{"url":"http:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2010\/12\/tartrate.jpg","type":"","width":"","height":""}],"author":"Henry Rzepa","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Henry Rzepa","Estimated reading time":"5 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3235#article","isPartOf":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3235"},"author":{"name":"Henry Rzepa","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#\/schema\/person\/2b40f7b9c872a4dc1547e040a11b6281"},"headline":"The handedness of DNA: an unheralded connection.","datePublished":"2010-12-29T10:14:24+00:00","dateModified":"2019-10-05T13:29:01+00:00","mainEntityOfPage":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3235"},"wordCount":965,"commentCount":8,"image":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3235#primaryimage"},"thumbnailUrl":"http:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2010\/12\/tartrate.jpg","keywords":["Bijvoet","chemist","chiroptical","d(CGCG)","Derek Barton","dispersion forces","DNA duplex","Historical","Marcus du Sautoy","Note","Odile Crick","professional artist","Tartaric Acid","van der Waals","watoc11","Watson Crick","Web sense","Z-DNA"],"articleSection":["Interesting chemistry"],"inLanguage":"en-GB","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3235#respond"]}]},{"@type":"WebPage","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3235","url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3235","name":"The handedness of DNA: an unheralded connection. - Henry Rzepa's Blog","isPartOf":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#website"},"primaryImageOfPage":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3235#primaryimage"},"image":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3235#primaryimage"},"thumbnailUrl":"http:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2010\/12\/tartrate.jpg","datePublished":"2010-12-29T10:14:24+00:00","dateModified":"2019-10-05T13:29:01+00:00","author":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#\/schema\/person\/2b40f7b9c872a4dc1547e040a11b6281"},"breadcrumb":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3235#breadcrumb"},"inLanguage":"en-GB","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3235"]}]},{"@type":"ImageObject","inLanguage":"en-GB","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3235#primaryimage","url":"http:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2010\/12\/tartrate.jpg","contentUrl":"http:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2010\/12\/tartrate.jpg"},{"@type":"BreadcrumbList","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3235#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog"},{"@type":"ListItem","position":2,"name":"The handedness of DNA: an unheralded connection."}]},{"@type":"WebSite","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#website","url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/","name":"Henry Rzepa's Blog","description":"Chemistry with a twist","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-GB"},{"@type":"Person","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#\/schema\/person\/2b40f7b9c872a4dc1547e040a11b6281","name":"Henry Rzepa","image":{"@type":"ImageObject","inLanguage":"en-GB","@id":"https:\/\/secure.gravatar.com\/avatar\/897b6740f7f599bca7942cdf7d7914af5988937ae0e3869ab09aebb87f26a731?s=96&d=blank&r=g370be3a7397865e4fd161aefeb0a5a85","url":"https:\/\/secure.gravatar.com\/avatar\/897b6740f7f599bca7942cdf7d7914af5988937ae0e3869ab09aebb87f26a731?s=96&d=blank&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/897b6740f7f599bca7942cdf7d7914af5988937ae0e3869ab09aebb87f26a731?s=96&d=blank&r=g","caption":"Henry Rzepa"},"description":"Henry Rzepa is Emeritus Professor of Computational Chemistry at Imperial College London.","sameAs":["https:\/\/orcid.org\/0000-0002-8635-8390"],"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?author=1"}]}},"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/pDef7-Qb","jetpack-related-posts":[{"id":3326,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3326","url_meta":{"origin":3235,"position":0},"title":"A comparison of left and right handed DNA double-helix models.","author":"Henry Rzepa","date":"January 1, 2011","format":false,"excerpt":"When Watson and Crick (WC) constructed their famous 3D model for DNA, they had to decide whether to make the double helix left or right handed. They chose a right-handed turn, on the grounds that their attempts at left-handed models all \"violated permissible van der Waals contacts\". No details of\u2026","rel":"","context":"In "Interesting chemistry"","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2011\/01\/CGCG.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":3908,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3908","url_meta":{"origin":3235,"position":1},"title":"Ferrocene","author":"Henry Rzepa","date":"April 17, 2011","format":false,"excerpt":"The structure of ferrocene was famously analysed by Woodward and Wilkinson in 1952,, symmetrically straddled in history by Pauling (1951) and Watson and Crick (1953). Quite a trio of Nobel-prize winning molecular structural analyses, all based on a large dose of intuition. The structures of both proteins and DNA succumbed\u2026","rel":"","context":"In "Interesting chemistry"","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2011\/04\/ferrocene-aim.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":6438,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=6438","url_meta":{"origin":3235,"position":2},"title":"Confirming the Fischer convention as a structurally correct representation of absolute configuration.","author":"Henry Rzepa","date":"March 13, 2012","format":false,"excerpt":"I wrote in an earlier post\u00a0how Pauling's\u00a0Nobel prize-winning suggestion in February 1951 of a (left-handed)\u00a0\u03b1-helical structure for proteins was based on the wrong absolute configuration of the amino acids (hence his helix should really have been the right-handed enantiomer). This was most famously established a few months later by Bijvoet's\u2026","rel":"","context":"In "Chiroptics"","block_context":{"text":"Chiroptics","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=2644"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":19159,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=19159","url_meta":{"origin":3235,"position":3},"title":"A form of life that can stably store genetic information using a six-letter, three-base-pair alphabet?","author":"Henry Rzepa","date":"December 2, 2017","format":false,"excerpt":"For around 16 years, Floyd Romesberg's group has been exploring un-natural alternatives (UBPs) to the Watson-Crick base pairs (C-G and A-T) that form part of the genetic code in DNA. Recently they have had remarkable success with one such base\u00a0pair, called X and Y (for the press) and dNaMTP and\u2026","rel":"","context":"In "Interesting chemistry"","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":23410,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=23410","url_meta":{"origin":3235,"position":4},"title":"The small-molecule antiviral compound Molnupiravir: an exploration of its tautomers.","author":"Henry Rzepa","date":"March 14, 2021","format":false,"excerpt":"For obvious reasons, anti-viral molecules are very much in the news at the moment. Thus Derek Lowe highlights Molnupiravir which is shown as a hydroxylamine, the representation originating from the Wikipedia page on the molecule. I like stereocentres more clearly identified using eg R\/S notation and so I went to\u2026","rel":"","context":"In "Interesting chemistry"","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/molnupiravir-1024x639.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":21499,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=21499","url_meta":{"origin":3235,"position":5},"title":"Prediction preceding experiment in chemistry – how unlucky was John Kirkwood?","author":"Henry Rzepa","date":"November 30, 2019","format":false,"excerpt":"Some areas of science progressed via very famous predictions that were subsequently verified by experiments. Think of Einstein and gravitational waves or of Dirac and the positron. There are fewer well-known examples in chemistry; perhaps Watson and Crick's prediction of the structure of DNA, albeit based on the interpretation of\u2026","rel":"","context":"In "Chiroptics"","block_context":{"text":"Chiroptics","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=2644"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2019\/12\/butan-2-ol-ORP-1024x312.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]}],"jetpack_likes_enabled":false,"authors":[{"term_id":2661,"user_id":1,"is_guest":0,"slug":"admin","display_name":"Henry Rzepa","avatar_url":"https:\/\/secure.gravatar.com\/avatar\/897b6740f7f599bca7942cdf7d7914af5988937ae0e3869ab09aebb87f26a731?s=96&d=blank&r=g","0":null,"1":"","2":"","3":"","4":"","5":"","6":"","7":"","8":""}],"_links":{"self":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/3235","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3235"}],"version-history":[{"count":13,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/3235\/revisions"}],"predecessor-version":[{"id":21388,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/3235\/revisions\/21388"}],"wp:attachment":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3235"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3235"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3235"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fppma_author&post=3235"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}