请输入您要查询的百科知识:

 

词条 Naphthoate synthase
释义

  1. Nomenclature

  2. Reaction

  3. Structure

  4. Homologs

  5. Cofactors/Inhibitors

  6. References

{{enzyme
| Name = 1,4-dihydroxy-2-naphthoyl-CoA synthase
| EC_number = 4.1.3.36
| CAS_number = 72506-71-9
| IUBMB_EC_number = 4/1/3/36
| GO_code = 0008935
| image = 4qii.jpg
| width = 270
| caption = 1,4-Dihydroxy-2-naphthoyl-CoA synthase hexamer, Mycobacterium tuberculosis

}}In enzymology 1,4-dihydroxy-2-naphthoyl-CoA synthase ({{EC number|4.1.3.36}}) is an enzyme that catalyzes the sixth step in the biosynthesis of phylloquinone and menaquinone, the two forms of vitamin K. In E. coli, 1,4-dihydroxy-2-naphthoyl-CoA synthase, formerly known as naphthoate synthase, is encoded by menB and uses O-succinylbenzoyl-CoA as a substrate and converts it to 1,4-dihydroxy-2-naphthoyl-CoA.[1]

Nomenclature

MenB is part of the crotonase fold super family, named after the crotonase fold in their structure.[1] The systematic name for MenB is 4-(2-carboxyphenyl)-4-oxobutanoyl-CoA dehydratase (cyclizing).[2] Other common names include:

  • Naphthoate synthase
  • 1,4-dihydroxy-2-naphthoate synthase
  • Dihydroxynaphthoate synthase
  • DHNA-CoA synthase

Reaction

[3]

It was originally thought that the product of this reaction had an oxygen where the SCoA currently resides, however; new research has shown that MenB only catalyzes the above reaction. There is a different enzyme that cleaves the SCoA and attaches the oxygen.

Structure

MenB is composed of two hexamers in an asymmetric unit, these hexamers are each composed of two trimers in an eclipsed arrangement. Each sub unit of the hexamers has three C terminal alpha helices, and a N terminal spiral core. These sub units come together to form the active site of the enzyme.[1]

The channel formed by alpha helices that can be seen in the middle of the enzyme leads to the active site. This opening exists on both top and bottom of the enzyme, allowing substrates different entry points to the active site, which rests in the middle of the enzyme.

Six different crystal structures have been studied for MenB in Escherichia coli their PDB codes are: 3t88, 3t89, 4els, 4elw, 4elx, and 4i42.

Other structures have been solved for this class of enzymes, with PDB accession codes {{PDB link|1Q51}}, {{PDB link|1Q52}}, {{PDB link|1RJM}}, {{PDB link|1RJN}}, and {{PDB link|2IEX}}.

Homologs

Homologous genes MenB exist in many different organisms, such as; Galium mollugo, Geobacillus kaustophilus, Mycobacterium phlei, Mycobacterium tuberculosis, Spinacia oleracea, and Staphylococcus aureus.[2]

MenB is only found in biosynthesis pathways in plants and bacteria, it does not exist in any other organisms. However, mammals require vitamin K in their diet because it is vital in the blood clotting process.

Cofactors/Inhibitors

MenB does not require any cofactors to catalyze the reaction.

In the organism Escherichia coli three inhibitors exist: 1-hydroxy-2-naphthoyl-CoA, 2,3-dihydroxybenzoyl-CoA, and 2,4-dihydroxybenzoyl-CoA.

References

1. ^{{Cite journal|title = Structural Basis of the Induced-Fit Mechanism of 1,4-Dihydroxy-2-Naphthoyl Coenzyme A Synthase from the Crotonase Fold Superfamily|date = April 26, 2013|pmc=3637252 | pmid=23658663|doi=10.1371/journal.pone.0063095|volume=8|journal=PLoS ONE|pages=e63095|vauthors=Sun Y, Song H, Li J, Li Y, Jiang M, Zhou J, Guo Z}}
2. ^{{Cite web|url = http://www.brenda-enzymes.info/enzyme.php?ecno=4.1.3.36|title = Information on EC 4.1.3.36 - 1,4-dihydroxy-2-naphthoyl-CoA synthase|date = July 2014|accessdate = December 2, 2014|website = BRENDA|publisher = }}
3. ^{{Cite journal |url= |vauthors=van Oostende C, Widhalm JR, Furt F, Ducluzeau AL, ((Basset GJC)) |date=2011 |title=Phylloquinone (Vitamin K1): function, enzymes and genes |journal=Advances in Botanical Research |editor=Fabrice Rébeillé |editor2=Roland Douce|editorlink2=Roland Douce |volume=59 |pages=229–61 |publisher=Academic Press |publication-place=Amsterdam |doi = 10.1016/B978-0-12-385853-5.00001-5 |pmid = }}
  • {{cite journal |vauthors=Kolkmann R, Leistner E | date = 1987 | title = 4-(2'-Carboxyphenyl)-4-oxobutyryl coenzyme A ester, an intermediate in vitamin K2 (menaquinone) biosynthesis | journal = Z. Naturforsch. C | volume = 42 | pages = 1207–14 | pmid = 2966501 | issue = 11–12 }}
  • {{cite journal |vauthors=Meganathan R, Bentley R | date = 1979 | title = Menaquinone (vitamin K2) biosynthesis: conversion of o-succinylbenzoic acid to 1,4-dihydroxy-2-naphthoic acid by Mycobacterium phlei enzymes | journal = J. Bacteriol. | volume = 140 | pages = 92–8 | pmid = 500558 | issue = 1 | pmc = 216783 }}
{{Carbon-carbon lyases}}{{Enzymes}}{{Portal bar|Molecular and Cellular Biology|border=no}}

2 : EC 4.1.3|Enzymes of known structure

随便看

 

开放百科全书收录14589846条英语、德语、日语等多语种百科知识,基本涵盖了大多数领域的百科知识,是一部内容自由、开放的电子版国际百科全书。

 

Copyright © 2023 OENC.NET All Rights Reserved
京ICP备2021023879号 更新时间:2024/9/21 18:41:32