The Bacterial View of the Periodic Table:Specific Functions for All Elements (Mini-Reviews特集「微生物生態と環境バイオテクノロジ-2」)

スポンサーリンク

概要

• 論文の詳細を見る

• Bacterial chromosomes have genes for transport of inorganic nutrient cations (such as NH_4^+, K+ Mg^<2+>, CO^<2+> , Fe^<3+>, Mn^<2+>, Zn^<2+> and other trace cations) and oxyanions (such as PO_4^<3-> and SO_4^<2-> and less abundant oxyanions). Together these account for sometimes several hundred genes in many bacteria. Bacterial plasmids encode resistance systems for toxic metal and metalloid ions including Ag^+, AsO_2^-, AsO_4^<3->, Cd^<2+>, CO^<2+>, CrO_4^<2->, Cu^<2+>, Hg^<2+>, Ni^<2+>, pb^<2+>, Sb^<3+>, TeO_3^<2->, T1^+, and Zn^<2+>. Most resistance systems function by energy-dependent efflux of toxic ions. A few involve enzymatic (mostly redox) transformants. Some of the efflux resistance systems are ATPases and others are chemiosmotic ion/proton exchangers. Mercury resistance is due to enzymatic detoxification with organomercurial lyase (cutting the C-Hg bond of compounds such as methylmercury and phenylmercury) and mercuric reductase (Hg^<2+>→Hg^0). The Cd^<2+>-resistance cation P-type ATPases of Gram-positive bacteria drives Cd^<2+> (and Zn^<2+>) efflux from resistant cells. The genes defective in the human hereditary diseases of copper metabolism, Menkes syndrome and Wilson's disease, encode Cu-specific P-type ATPases that are similar to bacterial Cd^<2+> ATPases. The arsenic resistance system transports arsenite [As(III)] , alternatively with the ArsB protein functioning as a chemiosmotic efflux transporter or with two proteins, ArsB and ArsA, functioning as an ATPase transporter. The third protein of the arsenic resistance system is an enzyme that reduces intracellular arsenate [As(V)] to arsenite [As(III)] , the substrate of the efflux system. In Gram negative cells, a three polypeptide complex functions as a chemiosmotic cation/proton exchanger to efflux Cd^<2+>, Zn^<2+>, and CO^<2+> . This pump consists of an inner membrane (CzcA), an outer membrane (CzcC) and a membrane-spanning (CzcB) protein that function together.

• 1998-09-30

著者

• SILVER Simon

  Department of Microbiology and Immunology, M/C 790, Room E704, University of Illinois at Chicago

• Silver S

  Department Of Microbiology And Immunology University Of Illinois

• Silver Simon

  Department Of Microbiology And Immunology M/c 790 University Of Illinois

関連論文

• The Bacterial View of the Periodic Table:Specific Functions for All Elements (Mini-Reviews特集「微生物生態と環境バイオテクノロジ-2」)
• Interactions between Two MerR Regulators and Three Operator/Promoter Regions in the Mercury Resistance Module of Bacillus megaterium
• Interactions between Two MerR Regulators and Three Operator/Promoter Regions in the Mercury Resistance Module of Bacillus megaterium
• Functional Dissection of a Mercuric Ion Transporter, MerC, from Acidithiobacillus ferrooxidans
• Mercuric Ion Uptake by Escherichia coli Cells Producing Thiobacillus ferrooxidans MerC

スポンサーリンク