{"id":229855,"date":"2025-06-08T13:30:06","date_gmt":"2025-06-08T13:30:06","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=229855"},"modified":"2025-06-08T13:30:08","modified_gmt":"2025-06-08T13:30:08","slug":"in-the-biosynthesis-of-brevotoxin-b-the-beastly-neurotoxin-whose-relatives-might-have-been-at-play-in-the-classic-hitchcock-film","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/06\/08\/in-the-biosynthesis-of-brevotoxin-b-the-beastly-neurotoxin-whose-relatives-might-have-been-at-play-in-the-classic-hitchcock-film\/","title":{"rendered":"In the biosynthesis of Brevotoxin B, the beastly neurotoxin whose relatives might have been at play in the classic Hitchcock film"},"content":{"rendered":"\n

In the biosynthesis of Brevotoxin B, the beastly neurotoxin whose relatives might have been at play in the classic Hitchcock film “The Birds,” which of the following functional groups react with inversion of stereochemistry (i.e. at the carbon being attacked) during the ring opening cascade? Your answer: a. cyclic ethers b. alkyl halides c. azides d. epoxides<\/p>\n\n\n\n

The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n

The correct answer is: d. epoxides<\/strong><\/p>\n\n\n\n

Explanation <\/h3>\n\n\n\n

In the biosynthesis of brevetoxin B<\/strong>, a polyether marine neurotoxin produced by the dinoflagellate Karenia brevis<\/em>, a cascade of epoxide-opening reactions<\/strong> plays a key role in constructing its complex polyether ladder structure. These reactions form the cyclic ethers that give brevetoxins their characteristic structure and bioactivity.<\/p>\n\n\n\n

During these biosynthetic steps, epoxides<\/strong> are the functional groups that undergo nucleophilic ring opening with inversion of stereochemistry<\/strong> at the carbon being attacked. This behavior is due to the nature of the epoxide ring: a three-membered ring strained and highly reactive toward nucleophiles.<\/p>\n\n\n\n

When a nucleophile attacks an epoxide, it does so via a backside attack<\/strong> mechanism, very similar to the SN2 mechanism in classical organic chemistry. This leads to inversion of configuration<\/strong> at the carbon center where the nucleophile attaches. In the context of brevetoxin biosynthesis, the nucleophile (typically a hydroxyl group or a water molecule) attacks the epoxide carbon, opening the ring and forming a new ether linkage with stereochemical inversion at that site.<\/p>\n\n\n\n

This stereospecificity<\/strong> is crucial in forming the correct three-dimensional geometry of the molecule, which in turn dictates its ability to bind and modulate voltage-gated sodium channels\u2014a key aspect of its neurotoxic effect.<\/p>\n\n\n\n

To clarify why other options are incorrect:<\/p>\n\n\n\n

    \n
  • a. Cyclic ethers<\/strong> (e.g., tetrahydrofuran) are relatively stable and not prone to nucleophilic attack unless under very specific, forcing conditions.<\/li>\n\n\n\n
  • b. Alkyl halides<\/strong> can undergo SN2 reactions with inversion, but they are not central to brevetoxin B biosynthesis.<\/li>\n\n\n\n
  • c. Azides<\/strong> are nucleophiles themselves and do not typically undergo SN2-type reactions with inversion as electrophiles.<\/li>\n<\/ul>\n\n\n\n

    Thus, epoxides (d)<\/strong> are the key functional groups that react with inversion of stereochemistry during the polyether-forming ring-opening cascade in brevetoxin B biosynthesis.<\/p>\n\n\n\n

    \"\"<\/figure>\n","protected":false},"excerpt":{"rendered":"

    In the biosynthesis of Brevotoxin B, the beastly neurotoxin whose relatives might have been at play in the classic Hitchcock film “The Birds,” which of the following functional groups react with inversion of stereochemistry (i.e. at the carbon being attacked) during the ring opening cascade? Your answer: a. cyclic ethers b. alkyl halides c. azides […]<\/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-229855","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/229855","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=229855"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/229855\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=229855"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=229855"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=229855"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}