The PduQ Enzyme Is an Alcohol Dehydrogenase Used to Recycle NAD+ Internally within the Pdu Microcompartment of Salmonella enterica

被引:63
作者
Cheng, Shouqiang [2 ]
Fan, Chenguang [3 ]
Sinha, Sharmistha [1 ]
Bobik, Thomas A. [1 ]
机构
[1] Iowa State Univ, Dept Biochem Biophys & Mol Biol, Ames, IA 50011 USA
[2] Northwestern Univ, Dept Microbiol Immunol, Feinberg Sch Med, Chicago, IL 60611 USA
[3] Yale Univ, Dept Mol Biophys & Biochem, New Haven, CT USA
来源
PLOS ONE | 2012年 / 7卷 / 10期
关键词
B-12-DEPENDENT 1,2-PROPANEDIOL DEGRADATION; L-THREONINE KINASE; SHELL PROTEIN; LISTERIA-MONOCYTOGENES; ESCHERICHIA-COLI; COENZYME-A; TYPHIMURIUM; ORGANELLES; ETHANOLAMINE; GENES;
D O I
10.1371/journal.pone.0047144
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
Salmonella enterica uses a bacterial microcompartment (MCP) for coenzyme B-12-dependent 1,2-propanediol (1,2-PD) utilization (Pdu). The Pdu MCP consists of a protein shell that encapsulates enzymes and cofactors required for metabolizing 1,2-PD as a carbon and energy source. Here we show that the PduQ protein of S. enterica is an iron-dependent alcohol dehydrogenase used for 1,2-PD catabolism. PduQ is also demonstrated to be a new component of the Pdu MCP. In addition, a series of in vivo and in vitro studies show that a primary function of PduQ is to recycle NADH to NAD(+) internally within the Pdu MCP in order to supply propionaldehyde dehydrogenase (PduP) with its required cofactor (NAD(+)). Genetic tests determined that a pduQ deletion mutant grew slower than wild-type Salmonella on 1,2-PD and that this phenotype was not complemented by a non-MCP associated Adh2 from Zymomonas that catalyzes the same reaction. This suggests that PduQ has a MCP-specific function. We also found that a pduQ deletion mutant had no growth defect in a genetic background having a second mutation that prevents MCP formation which further supports a MCP-specific role for PduQ. Moreover, studies with purified Pdu MCPs demonstrated that the PduQ enzyme can convert NADH to NAD(+) to supply the PduP reaction in vitro. Cumulatively, these studies show that the PduQ enzyme is used to recycle NADH to NAD(+) internally within the Pdu MCP. To our knowledge, this is the first report of internal recycling as a mechanism for cofactor homeostasis within a bacterial MCP.
引用
收藏
页数:11
相关论文
共 64 条