{"id":6857,"date":"2014-11-27T11:00:44","date_gmt":"2014-11-27T10:00:44","guid":{"rendered":"http:\/\/emblog.embl.de\/ells\/?page_id=6857"},"modified":"2021-06-23T09:02:16","modified_gmt":"2021-06-23T09:02:16","slug":"focus-on-insulin","status":"publish","type":"teachingbase","link":"https:\/\/www.embl.org\/ells\/teachingbase\/focus-on-insulin\/","title":{"rendered":"Focus on: Insulin"},"content":{"rendered":"\n<div class=\"vf-tabs\"><ul class=\"vf-tabs__list\" data-vf-js-tabs=\"true\"><li class=\"vf-tabs__item\"><a class=\"vf-tabs__link\" href=\"#vf-tabs__section-f96cf143-c40c-46ab-ba8b-84e41fde014c\">Overview<\/a><\/li><li class=\"vf-tabs__item\"><a class=\"vf-tabs__link\" href=\"#vf-tabs__section-8904878a-b65e-4ce4-80e6-51568c615b3a\">Info<\/a><\/li><li class=\"vf-tabs__item\"><a class=\"vf-tabs__link\" href=\"#vf-tabs__section-c3b73c14-0132-4d16-b4da-be8bca52a12e\">Primary<\/a><\/li><li class=\"vf-tabs__item\"><a class=\"vf-tabs__link\" href=\"#vf-tabs__section-1af92796-b70d-4daf-a861-c3b6928d7edf\">Secondary<\/a><\/li><li class=\"vf-tabs__item\"><a class=\"vf-tabs__link\" href=\"#vf-tabs__section-d94535f8-81b4-4691-bebb-b1ef4621058f\">Tertiary<\/a><\/li><li class=\"vf-tabs__item\"><a class=\"vf-tabs__link\" href=\"#vf-tabs__section-99c60f7b-cee6-48f4-9464-32e6960784a7\">Quaternary<\/a><\/li><li class=\"vf-tabs__item\"><a class=\"vf-tabs__link\" href=\"#vf-tabs__section-8c71fecb-a9e2-40c1-a1b0-aac7db2aad51\">Worksheet<\/a><\/li><li class=\"vf-tabs__item\"><a class=\"vf-tabs__link\" href=\"#vf-tabs__section-87d90ccb-95de-4a4a-9c85-ff6acc137f8d\">Quiz<\/a><\/li><li class=\"vf-tabs__item\"><a class=\"vf-tabs__link\" href=\"#vf-tabs__section-54bdb726-5329-4976-a0be-12538c5ad04f\">Optional material<\/a><\/li><\/ul><div class=\"vf-tabs-content\" data-vf-js-tabs-content=\"true\">\n<section class=\"vf-tabs__section\" id=\"vf-tabs__section-f96cf143-c40c-46ab-ba8b-84e41fde014c\"><h2>Overview<\/h2>\n<p>This teaching resource will guide you through consecutive steps to explore the biological structure of the insulin molecule \u2013 from primary to quaternary structure.<\/p>\n\n\n\n<p>How to start:<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Select the level of protein structure which you would like to work on via the tabs below.<\/li><li>Inform yourself about the structural details of insulin and follow the exercises.<\/li><li>Try to answer the questions in the Insulin quiz.<\/li><li>The Insulin worksheet can be printed out and worked on to test yourself on the structural biology of insulin. Color the structures and explore them in 3D!<\/li><\/ul>\n<\/section>\n\n\n\n<section class=\"vf-tabs__section\" id=\"vf-tabs__section-8904878a-b65e-4ce4-80e6-51568c615b3a\"><h2>Info<\/h2>\n<p><span style=\"color: #000000;\">Insulin is initially synthesized as&nbsp;<strong>preproinsulin<\/strong>, a 110 amino acid polypeptide&nbsp;that contains additional sequences:&nbsp;<\/span><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><span style=\"color: #000000;\">A \u201cpre\u201d amino-terminal sequence (signal&nbsp;peptide of 24 amino acids), which&nbsp;enables the secretion of the protein.<\/span><\/li><li><span style=\"color: #000000;\">A central \u201cpro\u201d sequence (the C peptide&nbsp;of 35 amino acids) which determines&nbsp;the correct folding of the protein.<\/span><\/li><\/ul>\n\n\n\n<p class=\"has-text-align-left\"><span style=\"color: #000000;\">After preproinsulin is translated in the&nbsp;endoplasmic reticulum, an enzyme&nbsp;cuts off the 24 amino-terminal amino&nbsp;acids, leaving proinsulin, which in turn&nbsp;folds and allows the formation of the&nbsp;disulphide bonds between cysteine residues.<\/span><br><span style=\"color: #000000;\">At this stage, the protein passes&nbsp;into the Golgi apparatus, where the C&nbsp;peptide is removed, forming mature insulin,&nbsp;which is then stored in the Golgi&nbsp;vesicles.<\/span><\/p>\n\n\n\n<p><span style=\"color: #000000;\">The <strong>mature insulin<\/strong> protein consists&nbsp;of two polypeptide chains (A- and B-chains). The A-chain is composed of 21 amino acids, the B-chain of 30 amino acids.<\/span><\/p>\n<\/section>\n\n\n\n<section class=\"vf-tabs__section\" id=\"vf-tabs__section-c3b73c14-0132-4d16-b4da-be8bca52a12e\"><h2>Primary<\/h2>\n<p>The mature insulin protein consists&nbsp;of two polypeptide chains (A- and B-chains). The A-chain is composed of 21 amino acids, the B-chain of 30 amino acids (find sequences below).<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Task: <\/strong><\/h3>\n\n\n\n<p>Compare the A-chains (and the B-chains) of human and pig insulins in the following activity by aligning their amino acid sequences. Are there any differences in the amino acid sequences?<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li>Copy the two amino acid&nbsp;sequences of&nbsp;human insulin and pig insulin which you find below. Select and copy the whole block of sequences starting with <em>&gt;sp<\/em> for the A-chains (step 1) and then for the B-chains (step 2).<\/li><li>Paste the sequences into the MUSCLE search box (shortcut Ctrl. + V).<\/li><li>In the \u201cSTEP 2\u2033 section ensure that \u201c<strong>Output Format<\/strong>\u201d is set at <strong>\u201cClustalW\u201d<\/strong>.<\/li><li>Click on the large <strong>\u201cSubmit<\/strong>\u201d button and your alignment will be processed.<\/li><li>You will see the results after a few seconds. Have a look at the alignment and answer the questions in the quiz.<\/li><\/ol>\n\n\n\n<p>Note: In order to submit the second set of sequences you may need to refresh your page and the MUSCLE search box will be empty again.<\/p>\n\n\n\n<p><strong>Step 1 \u2013 Compare the A-chains:<\/strong><br>&#8220;&gt;&gt;sp|P01308|90-110, Insulin A-chain, Human<br>GIVEQCCTSICSLYQLENYCN<br> &gt;sp|P01315|88-108, Insulin A-chain, Pig<br> GIVEQCCTSICSLYQLENYCN<\/p>\n\n\n\n<p><strong>Step2 \u2013 Compare the B-chains:<\/strong><br><span class=\"has-inline-color has-blue-color\">&gt;sp|P01308|25-54, Insulin B-chain, Human<\/span><br> FVNQHLCGSHLVEALYLVCGERGFFYTPKT<br>&gt;sp|P01315|25-54, Insulin B-chain, Pig<br>FVNQHLCGSHLVEALYLVCGERGFFYTPKA<\/p>\n\n\n<div\n  class=\"vf-embed vf-embed--custom-ratio\"\n\n  style=\"--vf-embed-max-width: 100%;\n    --vf-embed-custom-ratio-x: 640;\n    --vf-embed-custom-ratio-y: 320;\"\n><iframe loading=\"lazy\" width=\"640\" height=\"320\" src=\"https:\/\/www.ebi.ac.uk\/Tools\/msa\/muscle\/\" frameborder=\"0\" allow=\"accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen><\/iframe><\/div>\n<\/section>\n\n\n\n<section class=\"vf-tabs__section\" id=\"vf-tabs__section-1af92796-b70d-4daf-a861-c3b6928d7edf\"><h2>Secondary<\/h2>\n<div class=\"vf-grid | vf-grid__col-2\"><div><!--[vf\/content]-->\n<div class=\"vf-content\">\n\n<div class=\"wp-block-image\"><figure class=\"vf-figure  | vf-figure--align vf-figure--align-inline-start   size-large\"><a href=\"http:\/\/emblog.embl.de\/ells\/wp-content\/uploads\/2014\/11\/fig10-secB-color-label.png\"><img loading=\"lazy\" decoding=\"async\" width=\"406\" height=\"404\" class=\"vf-figure__image\" src=\"https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/fig10-secB-color-label-e1623765862853.png\" alt=\"\" class=\"wp-image-1425\" srcset=\"https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/fig10-secB-color-label-e1623765862853.png 406w, https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/fig10-secB-color-label-e1623765862853-300x300.png 300w, https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/fig10-secB-color-label-e1623765862853-150x150.png 150w\" sizes=\"auto, (max-width: 406px) 100vw, 406px\" \/><\/a><figcaption class=\"vf-figure__caption\">Insulin A-chain<\/figcaption><\/figure><\/div>\n\n<\/div>\n<\/div>\n\n\n<div><!--[vf\/content]-->\n<div class=\"vf-content\">\n\n<p>The secondary structure is determined by two a-helices in the A-chain.<\/p>\n\n<\/div>\n<\/div>\n<\/div>\n\n\n\n<div class=\"vf-grid | vf-grid__col-2\"><div><!--[vf\/content]-->\n<div class=\"vf-content\">\n\n<div class=\"wp-block-image wp-image-6863\"><figure class=\"vf-figure  | vf-figure--align vf-figure--align-inline-start   size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"509\" height=\"530\" class=\"vf-figure__image\" src=\"https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/fig9-A-color-e1623765958763.png\" alt=\"\" class=\"wp-image-1423\" srcset=\"https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/fig9-A-color-e1623765958763.png 509w, https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/fig9-A-color-e1623765958763-288x300.png 288w\" sizes=\"auto, (max-width: 509px) 100vw, 509px\" \/><figcaption class=\"vf-figure__caption\">Insulin B-chain<\/figcaption><\/figure><\/div>\n\n<\/div>\n<\/div>\n\n\n<div><!--[vf\/content]-->\n<div class=\"vf-content\">\n\n<p>The B-chain has a major a-helix section and a beta-sheet region. It folds sharply around the A-chain (see tertiary structure).<\/p>\n\n<\/div>\n<\/div>\n<\/div>\n\n\n\n<p><\/p>\n<\/section>\n\n\n\n<section class=\"vf-tabs__section\" id=\"vf-tabs__section-d94535f8-81b4-4691-bebb-b1ef4621058f\"><h2>Tertiary<\/h2>\n<div class=\"vf-grid | vf-grid__col-2\"><div><!--[vf\/content]-->\n<div class=\"vf-content\">\n\n<div class=\"wp-block-image\"><figure class=\"vf-figure  | vf-figure--align vf-figure--align-inline-start   size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"415\" height=\"566\" class=\"vf-figure__image\" src=\"https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/Insulin_tertiary_numb-e1623766022844.png\" alt=\"\" class=\"wp-image-1542\" srcset=\"https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/Insulin_tertiary_numb-e1623766022844.png 415w, https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/Insulin_tertiary_numb-e1623766022844-220x300.png 220w\" sizes=\"auto, (max-width: 415px) 100vw, 415px\" \/><\/figure><\/div>\n\n<\/div>\n<\/div>\n\n\n<div><!--[vf\/content]-->\n<div class=\"vf-content\">\n\n<p>The tertiary structure is stabilized by disulphide bridges (see insulin worksheet). The external part of the protein is polar, while internally it is mostly hydrophobic.<\/p>\n\n<\/div>\n<\/div>\n<\/div>\n\n\n\n<div class=\"vf-grid | vf-grid__col-2\"><div><!--[vf\/content]-->\n<div class=\"vf-content\">\n\n<div class=\"wp-block-image\"><figure class=\"vf-figure  | vf-figure--align vf-figure--align-inline-start   size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"456\" height=\"584\" class=\"vf-figure__image\" src=\"https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/fig6-e1623766058988.png\" alt=\"\" class=\"wp-image-1422\" srcset=\"https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/fig6-e1623766058988.png 456w, https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/fig6-e1623766058988-234x300.png 234w\" sizes=\"auto, (max-width: 456px) 100vw, 456px\" \/><\/figure><\/div>\n\n<\/div>\n<\/div>\n\n\n<div><!--[vf\/content]-->\n<div class=\"vf-content\">\n\n<p>Insulin is formed by two polypeptide chains (A- and B-chains), held together by two disulphide bridges; a third disulphide bridge is situated within the A-chain.<\/p>\n\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n\n\n\n<section class=\"vf-tabs__section\" id=\"vf-tabs__section-99c60f7b-cee6-48f4-9464-32e6960784a7\"><h2>Quaternary<\/h2>\n<figure class=\"vf-figure wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"500\" height=\"392\" class=\"vf-figure__image\" src=\"https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/Insulin-quaternary-structure_1-e1623766858559.png\" alt=\"\" class=\"wp-image-1543\"\/><\/figure>\n\n\n\n<p>As far as the quaternary structure is concerned insulin tends to form dimers in solution, owing to the formation of hydrogen bonds between the C-terminal ends of the B-chain.<\/p>\n<\/section>\n\n\n\n<section class=\"vf-tabs__section\" id=\"vf-tabs__section-8c71fecb-a9e2-40c1-a1b0-aac7db2aad51\"><h2>Worksheet<\/h2>\n<p>Download and print worksheet:<\/p>\n\n\n\n<div class=\"wp-block-file\"><a  href=\"https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/Insulin-worksheet-EMBLog.pdf\" class=\"wp-block-file__button vf-button vf-button--primary vf-button--pill vf-button--s\" download style=\"margin:0 0 0 .75em;\">Download<\/a><\/div>\n\n\n\n<p><\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Tasks<\/h2>\n\n\n\n<ol class=\"wp-block-list\"><li>Use your stereo glasses to explore the protein structure in 3D (upper left).&nbsp;<\/li><li>Color <strong>Insulin A-chain<\/strong> according to the color scheme below.<\/li><li>Color <strong>Insulin B-chain<\/strong> according to the color scheme below.<\/li><li>Color the following structures in the Insulin protein structure on the right: <ul><li>alpha helices<\/li><li>beta sheets<\/li><li>disulfide bonds <\/li><\/ul><\/li><\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">Coloring scheme:<\/h3>\n\n\n\n<ul class=\"wp-block-list\"><li>alpha helix \u2013 <strong><span style=\"color: #ff0000;\">red<\/span><\/strong><\/li><li>beta sheet \u2013 <strong><span style=\"color: #ffff00;\">yellow<\/span><\/strong><\/li><li>unstructured parts of the protein \u2013 <strong><span style=\"color: #008000;\">green<\/span><\/strong><\/li><li>Disulfide bonds \u2013 <strong><span style=\"color: #ff6600;\">orange<\/span><\/strong><\/li><li>N-terminus of protein \u2013 <span style=\"color: #0000ff;\"><strong>blue<\/strong><\/span><\/li><li>C-terminus of protein \u2013 <strong><span style=\"color: #800080;\">purple<\/span><\/strong><\/li><\/ul>\n<\/section>\n\n\n\n<section class=\"vf-tabs__section\" id=\"vf-tabs__section-87d90ccb-95de-4a4a-9c85-ff6acc137f8d\"><h2>Quiz<\/h2>\n<p>Take the <a href=\"https:\/\/play.kahoot.it\/v2\/lobby?quizId=2bf641ed-4c7a-41c6-8801-eab1d591787e\" target=\"_blank\" rel=\"noreferrer noopener\">revision quiz<\/a> and test your knowledge on this amazing molecule.<\/p>\n\n\n\n<div class=\"vf-grid | vf-grid__col-3\"><div><!--[vf\/content]-->\n<div class=\"vf-content\">\n\n<\/div>\n<\/div>\n\n\n<div><!--[vf\/content]-->\n<div class=\"vf-content\">\n\n<figure class=\"vf-figure wp-block-image size-large\"><a href=\"https:\/\/play.kahoot.it\/v2\/lobby?quizId=2bf641ed-4c7a-41c6-8801-eab1d591787e\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"419\" class=\"vf-figure__image\" src=\"https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/logo_kahoot_01-1024x419.png\" alt=\"\" class=\"wp-image-871\" srcset=\"https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/logo_kahoot_01-1024x419.png 1024w, https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/logo_kahoot_01-300x123.png 300w, https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/logo_kahoot_01-768x314.png 768w, https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/logo_kahoot_01-1536x628.png 1536w, https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/logo_kahoot_01.png 1590w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/a><\/figure>\n\n<\/div>\n<\/div>\n\n\n<div><!--[vf\/content]-->\n<div class=\"vf-content\">\n\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n\n\n\n<section class=\"vf-tabs__section\" id=\"vf-tabs__section-54bdb726-5329-4976-a0be-12538c5ad04f\"><h2>Optional material<\/h2>\n<h4 class=\"wp-block-heading\"><strong>Watch the <a href=\"https:\/\/www.embl.org\/ells\/insight-lecture\/embl-insight-lecture-2013\/\" data-type=\"insight-lecture\" data-id=\"18964\">EMBL Insight Lecture 2013<\/a> <em>\u201cFrom Code to Function \u2013 Observing Protein Synthesis Through the Electron Microscope\u201d<\/em><\/strong><\/h4>\n\n\n\n<div class=\"vf-grid | vf-grid__col-2\"><div><!--[vf\/content]-->\n<div class=\"vf-content\">\n\n<figure class=\"vf-figure wp-block-image size-large\"><a href=\"https:\/\/www.embl.org\/ells\/insight-lecture\/embl-insight-lecture-2013\/\"><img loading=\"lazy\" decoding=\"async\" width=\"567\" height=\"402\" class=\"vf-figure__image\" src=\"https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/protein-synthesis_web.png\" alt=\"\" class=\"wp-image-1367\" srcset=\"https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/protein-synthesis_web.png 567w, https:\/\/www.embl.org\/ells\/wp-content\/uploads\/2021\/05\/protein-synthesis_web-300x213.png 300w\" sizes=\"auto, (max-width: 567px) 100vw, 567px\" \/><\/a><figcaption class=\"vf-figure__caption\">Protein synthesis in the cell. Watch the EMBL Insight Lecture 2013 \u201cFrom Code to Function \u2013 Observing Protein Synthesis Through the Electron Microscope\u201d<\/figcaption><\/figure>\n\n<\/div>\n<\/div>\n\n\n<div><!--[vf\/content]-->\n<div class=\"vf-content\">\n\n<p>Christiane Schaffitzel and her team study the function and three-dimensional structure of ribosomes using a combination of molecular biology, biochemistry and cryo-electron microscopy. In her talk, Christiane gives an overview of the steps involved in protein synthesis and the role ribosomes play in the process. She then illustrates how her research group uses cryo-electron microscopy to study the structures of these fascinating molecules. Christiane\u2019s central research questions are: what we can learn from the make up of these fascinating molecules and how are synthesised proteins targeted to their destinations?<\/p>\n\n<\/div>\n<\/div>\n<\/div>\n\n\n\n<p><\/p>\n<\/section>\n<\/div><\/div>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Hands-on resource on the biological structure of the insulin molecule<\/p>\n","protected":false},"featured_media":923,"parent":0,"menu_order":9,"template":"","class_list":["post-6857","teachingbase","type-teachingbase","status-publish","has-post-thumbnail","hentry","age-group-16-19","topic-area-cell-biology","topic-area-structural-computational-biology"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.embl.org\/ells\/wp-json\/wp\/v2\/teachingbase\/6857","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.embl.org\/ells\/wp-json\/wp\/v2\/teachingbase"}],"about":[{"href":"https:\/\/www.embl.org\/ells\/wp-json\/wp\/v2\/types\/teachingbase"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.embl.org\/ells\/wp-json\/wp\/v2\/media\/923"}],"wp:attachment":[{"href":"https:\/\/www.embl.org\/ells\/wp-json\/wp\/v2\/media?parent=6857"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}