{"id":230804,"date":"2025-06-10T06:23:38","date_gmt":"2025-06-10T06:23:38","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=230804"},"modified":"2025-06-10T06:23:41","modified_gmt":"2025-06-10T06:23:41","slug":"a-small-generic-section-of-the-primary-structure-of-anhelix-is-given-by-amino-acid","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/06\/10\/a-small-generic-section-of-the-primary-structure-of-anhelix-is-given-by-amino-acid\/","title":{"rendered":"A small generic section of the primary structure of anhelix is given by -amino acid"},"content":{"rendered":"\n<p>A small generic section of the primary structure of an<br>helix is given by -amino acid<br>1-amino acid<br>-2amino acid<br>-3amino acid<br>-4amino acid<br>-5amino acid<br>-6amino acid<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Which amino acid residue&#8217;s backbone forms a hydrogen bond with the backbone of the first (1\\textsuperscript{st}) residue<\/li>\n<\/ul>\n\n\n\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-0-color\">The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n<p><strong>Correct Answer:<\/strong> The <strong>fifth (5\u1d57\u02b0)<\/strong> amino acid residue&#8217;s backbone forms a hydrogen bond with the backbone of the <strong>first (1\u02e2\u1d57)<\/strong> residue in an <strong>\u03b1-helix<\/strong>.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Explanation<\/strong><\/h3>\n\n\n\n<p>In an <strong>\u03b1-helix<\/strong>, a common secondary structure in proteins, the polypeptide chain coils into a right-handed spiral stabilized by <strong>intramolecular hydrogen bonds<\/strong>. These hydrogen bonds occur between the <strong>carbonyl oxygen (C=O)<\/strong> of one amino acid and the <strong>amide hydrogen (N-H)<\/strong> of another.<\/p>\n\n\n\n<p>Specifically, the hydrogen bond forms between the <strong>carbonyl oxygen of the amino acid at position <em>i<\/em><\/strong> and the <strong>amide hydrogen of the amino acid at position <em>i+4<\/em><\/strong>. This is often referred to as the <em>i \u2192 i+4 hydrogen bonding pattern<\/em>. Therefore, in this pattern:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>The <strong>1\u02e2\u1d57 residue<\/strong> (i) forms a hydrogen bond with the <strong>5\u1d57\u02b0 residue<\/strong> (i+4).<\/li>\n\n\n\n<li>The <strong>2\u207f\u1d48 residue<\/strong> forms a hydrogen bond with the <strong>6\u1d57\u02b0<\/strong>, and so on.<\/li>\n<\/ul>\n\n\n\n<p>This pattern helps stabilize the helical structure and is crucial to the \u03b1-helix\u2019s integrity.<\/p>\n\n\n\n<p>The side chains (R-groups) of the amino acids in an \u03b1-helix project outward from the helical backbone, minimizing steric hindrance and maximizing hydrogen bonding. The result is a compact, stable structure commonly found in transmembrane proteins, DNA-binding proteins, and structural motifs like coiled-coils.<\/p>\n\n\n\n<p>The \u03b1-helix typically has:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>3.6 residues per turn<\/strong>,<\/li>\n\n\n\n<li>A rise of <strong>1.5 \u00c5 per residue<\/strong>,<\/li>\n\n\n\n<li>A pitch (height per full turn) of about <strong>5.4 \u00c5<\/strong>.<\/li>\n<\/ul>\n\n\n\n<p>Knowing that hydrogen bonding occurs between every fourth residue in the backbone allows us to deduce that in a small segment of seven amino acids, the first residue\u2019s backbone will form a hydrogen bond with the fifth.<\/p>\n\n\n\n<p>This characteristic hydrogen bonding pattern is fundamental to the \u03b1-helix\u2019s stability and function in biological systems.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" src=\"https:\/\/learnexams.com\/blog\/wp-content\/uploads\/2025\/06\/learnexams-banner4-792.jpeg\" alt=\"\" class=\"wp-image-230805\"\/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>A small generic section of the primary structure of anhelix is given by -amino acid1-amino acid-2amino acid-3amino acid-4amino acid-5amino acid-6amino acid The Correct Answer and Explanation is: Correct Answer: The fifth (5\u1d57\u02b0) amino acid residue&#8217;s backbone forms a hydrogen bond with the backbone of the first (1\u02e2\u1d57) residue in an \u03b1-helix. Explanation In an \u03b1-helix, [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-230804","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/230804","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=230804"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/230804\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=230804"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=230804"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=230804"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}