Heme-Dependent Rubber Oxygenase RoxA of Xanthomonas sp. Cleaves the Carbon Backbone of Poly( cis -1,4-Isoprene) by a Dioxygenase Mechanism

Author:

Braaz Reinhard1,Armbruster Wolfgang2,Jendrossek Dieter1

Affiliation:

1. Institut für Mikrobiologie, Universität Stuttgart

2. Institut für Lebensmittelchemie, Universität Hohenheim, Stuttgart, Germany

Abstract

ABSTRACT Oxidative cleavage of poly( cis -1,4-isoprene) by rubber oxygenase RoxA purified from Xanthomonas sp. was investigated in the presence of different combinations of 16 O 2 , 18 O 2 , H 2 16 O, and H 2 18 O. 12-Oxo-4,8-dimethyl-trideca-4,8-diene-1-al (ODTD; m / z 236) was the main cleavage product in the absence of 18 O-compounds. Incorporation of one 18 O atom in ODTD was found if the cleavage reaction was performed in the presence of 18 O 2 and H 2 16 O. Incubation of poly( cis -1,4-isoprene) (with RoxA) or of isolated unlabeled ODTD (without RoxA) with H 2 18 O in the presence of 16 O 2 indicated that the carbonyl oxygen atoms of ODTD significantly exchanged with oxygen atoms derived from water. The isotope exchange was avoided by simultaneous enzymatic reduction of both carbonyl functions of ODTD to the corresponding dialcohol (12-hydroxy-4,8-dimethyl-trideca-4,8-diene-1-ol (HDTD; m / z 240) during RoxA-mediated in vitro cleavage of poly( cis -1,4-isoprene). In the presence of 18 O 2 , H 2 16 O, and alcohol dehydrogenase/NADH, incorporation of two atoms of 18 O into the reduced metabolite HDTD was found ( m / z 244), revealing that RoxA cleaves rubber by a dioxygenase mechanism. Based on the labeling results and the presence of two hemes in RoxA, a model of the enzymatic cleavage mechanism of poly( cis -1,4-isoprene) is proposed.

Publisher

American Society for Microbiology

Subject

Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology

Cited by 66 articles. 订阅此论文施引文献 订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3