A Conserved Domain in Escherichia coli Lon Protease Is Involved in Substrate Discriminator Activity

Author:

Ebel Wolfgang1,Skinner Monica M.1,Dierksen Karen P.1,Scott Janelle M.1,Trempy Janine E.1

Affiliation:

1. Department of Microbiology, Oregon State University, Corvallis, Oregon 97331-3804

Abstract

ABSTRACT Lon protease of Escherichia coli regulates a diverse set of physiological responses including cell division, capsule production, plasmid stability, and phage replication. Little is known about the mechanism of substrate recognition by Lon. To examine the interaction of Lon with two of its substrates, RcsA and SulA, we generated point mutations in lon which affected its substrate specificity. The most informative lon mutant overproduced capsular polysaccharide (RcsA stabilized) yet was resistant to DNA-damaging agents (SulA degraded). Immunoblots revealed that RcsA protein persisted in this mutant whereas SulA protein was rapidly degraded. The mutant contains a single-base change within lon leading to a single amino acid change of glutamate 240 to lysine. E240 is conserved among all Lon isolates and resides in a charged domain that has a high probability of adopting a coiled-coil conformation. This conformation, implicated in mediating protein-protein interactions, appears to confer substrate discriminator activity on Lon. We propose a model suggesting that this coiled-coil domain represents the discriminator site of Lon.

Publisher

American Society for Microbiology

Subject

Molecular Biology,Microbiology

Reference65 articles.

1. Cloning, structure and expression of the full-size lon gene in Escherichia coli coding for ATP-dependent La-proteinase;Amerik A.;Bioorg. Khim.,1990

2. Site-directed mutagenesis of La protease. A catalytically active serine residue;Amerik A. Y.;FEBS Lett.,1991

3. Mutation blocking the specific degradation of reinitiation polypeptides in E. coli;Apte B. N.;Nature,1975

4. Fine-structure mapping and identification of two regulators of capsule synthesis in Escherichia coli K-12

5. Mutants of Escherichia coli with a defect in the degradation of nonsense fragments;Bukhari A. I.;Nature,1973

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