{"id":396,"date":"2023-03-17T05:38:22","date_gmt":"2023-03-17T05:38:22","guid":{"rendered":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/?post_type=chapter&#038;p=396"},"modified":"2023-04-07T11:26:11","modified_gmt":"2023-04-07T11:26:11","slug":"prokaryotic-translation","status":"publish","type":"chapter","link":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/chapter\/prokaryotic-translation\/","title":{"raw":"Prokaryotic Translation","rendered":"Prokaryotic Translation"},"content":{"raw":"<h1 style=\"text-align: center\">Translation<\/h1>\r\n<ul>\r\n \t<li style=\"text-align: justify\"><span>Translation is the last step in gene expression, <\/span><\/li>\r\n \t<li style=\"text-align: justify\"><span>During translation\u00a0 the coding sequence of mRNA is translated into the amino-acid sequence of a protein. <\/span><\/li>\r\n \t<li style=\"text-align: justify\"><span>Translation is a highly dynamic process and comprises\u00a0 four major phases: initiation, elongation, termination, and ribosome recycling. <\/span><\/li>\r\n \t<li style=\"text-align: justify\"><span>Ribosomes form transient complexes with auxiliary translation factors during each phase of translation and\u00a0 facilitate protein synthesis.\u00a0<\/span><\/li>\r\n<\/ul>\r\n<h1 style=\"text-align: center\">Translation in Prokaryotes<\/h1>\r\n<ul>\r\n \t<li style=\"text-align: justify\"><span>In bacteria, translation initiation occurs co transcriptionally. The RNA polymerase (RNAP) and the ribosome physically interact with each other.<\/span><\/li>\r\n \t<li style=\"text-align: justify\"><span>The ribosome binds to the ribosome binding site (RBS) of the mRNA as soon as it emerges from the RNAP.<\/span><\/li>\r\n<\/ul>\r\n<h1>Initiation<\/h1>\r\n<ul>\r\n \t<li style=\"text-align: justify\"><span>During translation initiation, the ribosome recruits an mRNA and selects the start codon of the O<strong>pen Reading Frame (ORF)\u00a0<\/strong><\/span><\/li>\r\n \t<li style=\"text-align: justify\">m RNAS of prokaryotes <span>have an extended <strong>5\u2032 untranslated region (5\u2032UTR)<\/strong> and an <strong>[pb_glossary id=\"936\"]Shine- Dalgarno sequence [\/pb_glossary](SD)<\/strong> located 8\u201310 nt upstream of the start codon (usually AUG).<\/span><\/li>\r\n \t<li style=\"text-align: justify\"><span>Interactions between the SD sequence and the complementary anti-SD (aSD) sequence in 16S ribosomal RNA (rRNA) recruits the small 30 S ribosomal subunit and anchors \u00a0the 30S ribosomal subunit at the correct location on the mRNA template.<\/span><\/li>\r\n \t<li style=\"text-align: justify\"><span>Initiation is promoted by initiation factors IF1, IF2, and IF3. IF1 enhances the activities of IF2 and IF3.IF2 is a GTPase that recruits the initiator fMet-tRNA<sup>fMet<\/sup>. IF3 interferes with subunit association. It also ensures the fidelity of fMet-tRNA<sup>fMet<\/sup>\u00a0selection over the elongator aminoacyl-tRNAs (aa-tRNAs), and helps to discriminate against mRNAs with unfavorable translation initiation regions (TIRs)<\/span><\/li>\r\n \t<li style=\"text-align: justify\"><span>The initiator tRNA then interacts with the\u00a0<\/span><span id=\"term581\" data-type=\"term\">start codon<\/span><span> AUG (or rarely, GUG).\u00a0<\/span><span>This tRNA carries the amino acid methionine, which is formylated after its attachment to the tRNA and thus the\u00a0 <strong>Charged t RNA<\/strong> , <\/span><span>fMet-tRNA<\/span><sup>Metf\u00a0 \u00a0<\/sup><span> is formed .\u00a0 This is mediated by the initiation factor IF-2.<\/span><\/li>\r\n \t<li style=\"text-align: justify\"><span>The initiating fMet <\/span><span>is usually removed after translation is complete.<\/span><\/li>\r\n \t<li style=\"text-align: justify\"><span>After the formation of the initiation complex, the 30S ribosomal subunit is joined by the 50S subunit to form the 70S translation complex.\u00a0<\/span><\/li>\r\n<\/ul>\r\n<img src=\"http:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-content\/uploads\/sites\/17\/2023\/03\/Prokaryotic_Translation_Initiation-1024x1024.png\" alt=\"Picture depicting the steps in the initiation of translation in prokaryotes of\" width=\"1024\" height=\"1024\" class=\"aligncenter size-large wp-image-422\" \/>\r\n<p style=\"text-align: center\"><span style=\"color: #993366;background-color: #ffffff\"><a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:Prokaryotic_Translation_Initiation.png\" target=\"_blank\" rel=\"noopener\" style=\"color: #993366;background-color: #ffffff\">\"Prokaryotic Translation Initiation\"<\/a>\u00a0by\u00a0<a style=\"color: #993366;background-color: #ffffff\">Richard Wheeler (Zephyris) via wikimedia\u00a0<\/a><a style=\"color: #993366;background-color: #ffffff\"><\/a><a style=\"color: #993366;background-color: #ffffff\"><\/a>is licensed under\u00a0<a href=\"http:\/\/creativecommons.org\/licenses\/by-sa\/3.0\" target=\"_blank\" rel=\"noopener\" style=\"color: #993366;background-color: #ffffff\">CC BY-SA 3.0<\/a><\/span><\/p>\r\n\r\n<ul>\r\n \t<li><span>The ribosome consists of three compartments. <\/span>\r\n<ul>\r\n \t<li><span><strong>The A (aminoacyl) site\u00a0 :<\/strong> the incoming charged aminoacyl tRNAs binds to this site.<\/span><\/li>\r\n \t<li><span><strong>The P (peptidyl) site\u00a0 :<\/strong> binds charged tRNAs carrying amino acids that have formed peptide bonds with the growing polypeptide chain but have not yet dissociated from their corresponding tRNA. <\/span><\/li>\r\n \t<li><span><strong>The E (exit) site\u00a0 :<\/strong>\u00a0 The uncharged t RNA\u00a0 ( t RNA after delivering the aminoacid) are released from this site.<\/span><\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n<span>\u00a0<\/span>\r\n\r\n&nbsp;","rendered":"<h1 style=\"text-align: center\">Translation<\/h1>\n<ul>\n<li style=\"text-align: justify\"><span>Translation is the last step in gene expression, <\/span><\/li>\n<li style=\"text-align: justify\"><span>During translation\u00a0 the coding sequence of mRNA is translated into the amino-acid sequence of a protein. <\/span><\/li>\n<li style=\"text-align: justify\"><span>Translation is a highly dynamic process and comprises\u00a0 four major phases: initiation, elongation, termination, and ribosome recycling. <\/span><\/li>\n<li style=\"text-align: justify\"><span>Ribosomes form transient complexes with auxiliary translation factors during each phase of translation and\u00a0 facilitate protein synthesis.\u00a0<\/span><\/li>\n<\/ul>\n<h1 style=\"text-align: center\">Translation in Prokaryotes<\/h1>\n<ul>\n<li style=\"text-align: justify\"><span>In bacteria, translation initiation occurs co transcriptionally. The RNA polymerase (RNAP) and the ribosome physically interact with each other.<\/span><\/li>\n<li style=\"text-align: justify\"><span>The ribosome binds to the ribosome binding site (RBS) of the mRNA as soon as it emerges from the RNAP.<\/span><\/li>\n<\/ul>\n<h1>Initiation<\/h1>\n<ul>\n<li style=\"text-align: justify\"><span>During translation initiation, the ribosome recruits an mRNA and selects the start codon of the O<strong>pen Reading Frame (ORF)\u00a0<\/strong><\/span><\/li>\n<li style=\"text-align: justify\">m RNAS of prokaryotes <span>have an extended <strong>5\u2032 untranslated region (5\u2032UTR)<\/strong> and an <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_396_936\">Shine- Dalgarno sequence <\/a>(SD)<\/strong> located 8\u201310 nt upstream of the start codon (usually AUG).<\/span><\/li>\n<li style=\"text-align: justify\"><span>Interactions between the SD sequence and the complementary anti-SD (aSD) sequence in 16S ribosomal RNA (rRNA) recruits the small 30 S ribosomal subunit and anchors \u00a0the 30S ribosomal subunit at the correct location on the mRNA template.<\/span><\/li>\n<li style=\"text-align: justify\"><span>Initiation is promoted by initiation factors IF1, IF2, and IF3. IF1 enhances the activities of IF2 and IF3.IF2 is a GTPase that recruits the initiator fMet-tRNA<sup>fMet<\/sup>. IF3 interferes with subunit association. It also ensures the fidelity of fMet-tRNA<sup>fMet<\/sup>\u00a0selection over the elongator aminoacyl-tRNAs (aa-tRNAs), and helps to discriminate against mRNAs with unfavorable translation initiation regions (TIRs)<\/span><\/li>\n<li style=\"text-align: justify\"><span>The initiator tRNA then interacts with the\u00a0<\/span><span id=\"term581\" data-type=\"term\">start codon<\/span><span> AUG (or rarely, GUG).\u00a0<\/span><span>This tRNA carries the amino acid methionine, which is formylated after its attachment to the tRNA and thus the\u00a0 <strong>Charged t RNA<\/strong> , <\/span><span>fMet-tRNA<\/span><sup>Metf\u00a0 \u00a0<\/sup><span> is formed .\u00a0 This is mediated by the initiation factor IF-2.<\/span><\/li>\n<li style=\"text-align: justify\"><span>The initiating fMet <\/span><span>is usually removed after translation is complete.<\/span><\/li>\n<li style=\"text-align: justify\"><span>After the formation of the initiation complex, the 30S ribosomal subunit is joined by the 50S subunit to form the 70S translation complex.\u00a0<\/span><\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"http:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-content\/uploads\/sites\/17\/2023\/03\/Prokaryotic_Translation_Initiation-1024x1024.png\" alt=\"Picture depicting the steps in the initiation of translation in prokaryotes of\" width=\"1024\" height=\"1024\" class=\"aligncenter size-large wp-image-422\" srcset=\"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-content\/uploads\/sites\/17\/2023\/03\/Prokaryotic_Translation_Initiation.png 1024w, https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-content\/uploads\/sites\/17\/2023\/03\/Prokaryotic_Translation_Initiation-300x300.png 300w, https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-content\/uploads\/sites\/17\/2023\/03\/Prokaryotic_Translation_Initiation-150x150.png 150w, https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-content\/uploads\/sites\/17\/2023\/03\/Prokaryotic_Translation_Initiation-768x768.png 768w, https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-content\/uploads\/sites\/17\/2023\/03\/Prokaryotic_Translation_Initiation-65x65.png 65w, https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-content\/uploads\/sites\/17\/2023\/03\/Prokaryotic_Translation_Initiation-225x225.png 225w, https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-content\/uploads\/sites\/17\/2023\/03\/Prokaryotic_Translation_Initiation-350x350.png 350w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/p>\n<p style=\"text-align: center\"><span style=\"color: #993366;background-color: #ffffff\"><a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:Prokaryotic_Translation_Initiation.png\" target=\"_blank\" rel=\"noopener\" style=\"color: #993366;background-color: #ffffff\">&#8220;Prokaryotic Translation Initiation&#8221;<\/a>\u00a0by\u00a0<a style=\"color: #993366;background-color: #ffffff\">Richard Wheeler (Zephyris) via wikimedia\u00a0<\/a><a style=\"color: #993366;background-color: #ffffff\"><\/a><a style=\"color: #993366;background-color: #ffffff\"><\/a>is licensed under\u00a0<a href=\"http:\/\/creativecommons.org\/licenses\/by-sa\/3.0\" target=\"_blank\" rel=\"noopener\" style=\"color: #993366;background-color: #ffffff\">CC BY-SA 3.0<\/a><\/span><\/p>\n<ul>\n<li><span>The ribosome consists of three compartments. <\/span>\n<ul>\n<li><span><strong>The A (aminoacyl) site\u00a0 :<\/strong> the incoming charged aminoacyl tRNAs binds to this site.<\/span><\/li>\n<li><span><strong>The P (peptidyl) site\u00a0 :<\/strong> binds charged tRNAs carrying amino acids that have formed peptide bonds with the growing polypeptide chain but have not yet dissociated from their corresponding tRNA. <\/span><\/li>\n<li><span><strong>The E (exit) site\u00a0 :<\/strong>\u00a0 The uncharged t RNA\u00a0 ( t RNA after delivering the aminoacid) are released from this site.<\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><span>\u00a0<\/span><\/p>\n<p>&nbsp;<\/p>\n<div class=\"glossary\"><span class=\"screen-reader-text\" id=\"definition\">definition<\/span><template id=\"term_396_936\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_396_936\"><div tabindex=\"-1\"><p>The nucleotide sequence located 8-10 nucleotides upstream of the start codon.Interaction between the complementary anti-SD  sequence in 16S ribosomal RNA recruits 30S ribosomal subuni at the correct location on the m RNA <\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><\/div>","protected":false},"author":5,"menu_order":17,"template":"","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_uf_show_specific_survey":0,"_uf_disable_surveys":false,"pb_show_title":"on","pb_short_title":"Prokaryotic Translation","pb_subtitle":"Prokaryotic Translation","pb_authors":["dr-v-malathi"],"pb_section_license":"cc-by-sa"},"chapter-type":[],"contributor":[61],"license":[54],"class_list":["post-396","chapter","type-chapter","status-publish","hentry","contributor-dr-v-malathi","license-cc-by-sa"],"aioseo_notices":[],"part":3,"_links":{"self":[{"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/pressbooks\/v2\/chapters\/396","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/wp\/v2\/users\/5"}],"version-history":[{"count":30,"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/pressbooks\/v2\/chapters\/396\/revisions"}],"predecessor-version":[{"id":1062,"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/pressbooks\/v2\/chapters\/396\/revisions\/1062"}],"part":[{"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/pressbooks\/v2\/parts\/3"}],"metadata":[{"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/pressbooks\/v2\/chapters\/396\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/wp\/v2\/media?parent=396"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/pressbooks\/v2\/chapter-type?post=396"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/wp\/v2\/contributor?post=396"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.justwrite.in\/understanding-gene-regulation\/wp-json\/wp\/v2\/license?post=396"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}