AB5 toxin

AB5 toxin

The AB5 (or AB5) toxins are six-component protein complexes secreted by a number of pathogenic bacteria. All share a similar structure and mechanism for entering targeted host cells.cite journal |author = Merritt E, Hol W |title=AB5 toxins |journal=Curr Opin Struct Biol |volume=5 |issue=2 |pages=165–71 |year=1995 |pmid=7648317 |doi=10.1016/0959-440X(95)80071-9]

Structure and mechanism

A complete AB5 toxin complex contains six protein units. Five – the B subunits – are similar or identical in structure; the remaining A subunit is unique.

The A subunit (or a portion thereof) of an AB5 toxin is the portion of the complex responsible for toxicity. Typically it will have enzymatic activity inside the host cell.

The B subunits form a pentameric (five-membered) ring, into which one end of the A subunit extends and is held. This B subunit ring is also capable of binding to a receptor on the surface of the host cell.cite journal |author=Lencer W, Saslowsky D |title=Raft trafficking of AB5 subunit bacterial toxins |journal=Biochim Biophys Acta |volume=1746 |issue=3 |pages=314–21 |year=2005 |pmid=16153723 |doi=10.1016/j.bbamcr.2005.07.007] (Without the B subunits, the A subunit has no way of attaching to or entering the cell, and thus no way to exert its toxic effect.)

List of AB5 toxins

*"Campylobacter jejuni" enterotoxin (from "Campylobacter jejuni")
*cholera toxin ("Vibrio cholerae")
*heat-labile enterotoxins (LT and LT-II) ("Escherichia coli")
*pertussis toxin ("Bordetella pertussis")
*shiga toxin ("Shigella dysenteriae")
*shiga-like toxin (or "verotoxin") (enterohemorrhagic varieties of "E. coli" including )

References


Wikimedia Foundation. 2010.

Игры ⚽ Нужно решить контрольную?

Look at other dictionaries:

  • AB5 — may refer to: * AB5 toxin * Abelian Category …   Wikipedia

  • Toxin — This article is about the class of poisonous substances. For other uses, see Toxin (disambiguation). Universal warning symbol used to indicate toxic substances or environments A toxin (from Ancient Greek: τοξικόν toxikon) is a poisonous… …   Wikipedia

  • Cholera toxin — (sometimes abbreviated to CTX, Ctx, or CT) is a protein complex secreted by the bacterium Vibrio cholerae.[1][2] CTX is responsible for the massive, watery diarrhea characteristic of cholera infection. Contents 1 Structure …   Wikipedia

  • Botulinum toxin — Clinical data Pregnancy cat.  ? Legal status  ? (US) Rout …   Wikipedia

  • Diphtheria toxin — Diphtheria toxin, C domain complex of diphtheria toxin and heparin binding epidermal growth factor Identifiers Symbol Diphtheria C Pfam …   Wikipedia

  • Shiga-like toxin — is a AB5 type Shiga toxin produced by the bacteria Escherichia coli and also known as verotoxin. In 1977, researchers in Ottawa, Ontario rediscovered the Shiga toxin produced by Shigella dysenteriae in E. coli . [cite journal |author=Konowalchuk… …   Wikipedia

  • Clostridium perfringens alpha toxin — Crystal structure of Clostridium perfringens alpha toxin Identifiers Symbol  ? …   Wikipedia

  • Shiga toxin — Shiga toxins are a family of related toxins with two major groups, Stx1 and Stx2, whose genes are considered to be part of the genome of lambdoid prophages.cite journal |author=Friedman D, Court D |title=Bacteriophage lambda: alive and well and… …   Wikipedia

  • Clostridium difficile toxin B — cytotoxin Structure of C. difficile glucosyl transferase Toxin B showing UDP and glusose from PDB entry 2BVM [1] Identifiers …   Wikipedia

  • Clostridium difficile toxin A — is a toxin generated by Clostridium difficile.[1] It is similar to Clostridium difficile Toxin B. It is usually described as a enterotoxin,[2] but it also has some activity as a cytotoxin.[3] References …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”