Cobalamin-mediated mercury methylation by Desulfovibrio desulfuricans LS

Author:

Choi S C1,Bartha R1

Affiliation:

1. Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, New Jersey.

Abstract

The prominence of sulfate reducers in mercury biomethylation prompted the examination of the methyl carrier and mercury methylation activity of Desulfovibrio desulfuricans LS. There was a low degree of mercury tolerance and a high degree of methylation during fermentative growth; the opposite was true during sulfate reduction. During 2 days of fermentative growth, up to 37% of HgCl2 was methylated at 0.1 micrograms/ml, but only 1.5% was methylated at 10.0 micrograms/ml. Less than 1% of the added HgCl2 was methylated under sulfate-reducing conditions. D. desulfuricans LS radioimmunoassay results were positive for cobalamin. The addition of CoCl2 and benzimidazole to fermentative cultures increased methylation activity. From D. desulfuricans LS grown in the presence of (57)CoCl2, a corrinoid was extracted and purified. High-performance liquid chromatography analysis of the purified extract yielded a single peak with the retention time of cobalamin, and 97% of the (57)Co radioactivity was associated with this peak. Fast atom bombardment and UV and visible spectra of the isolated corrinoid matched those of cobalamin. When methylated with (14)CH3I, the isolated corrinoid methylated Hg(2+) with a 93.9% preservation of (14)C specific activity. We conclude that D. desulfuricans LS methylates mercury via cobalamin (vitamin B12). Under physiological conditions, the enzymatic catalysis of this reaction is likely.

Publisher

American Society for Microbiology

Subject

Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology

Reference25 articles.

1. Fast atom bombardment mass spectrometry of cobalamines;Barber M.;Biomed. Mass Spectrometr.,1981

2. Berman M. 1988. Ph.D. thesis. Rutgers University New Brunswick N.J.

3. Carbon flow in mercury biomethylation by Desulfovibrio desulfuricans;Berman M.;Appl. Environ. Microbiol.,1990

4. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding;Bradford M. M.;Anal. Biochem.,1976

5. Choi S.-C. M. Berman and R. Bartha. 1991. Evidence for a novel Hg 2+-methylating corrinoid in Desulfovibrio desulfuricans abstr. Q-261 p. 320. Abstr. 91st Gen. Meet. Am. Soc. Microbiol. 1991. American Society for Microbiology Washington D.C.

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