PBP1a glycosyltransferase and transpeptidase activities are both required for maintaining cell morphology and envelope integrity in Shewanella oneidensis. Issue 3 (10th February 2020)

• Record Type: Journal Article
• Authors: Yin, Jianhua; Zhang, Ting; Cai, Jingxiao; Lou, Jie; Cheng, Dan; Zhou, Weifeng; Xu, Chaoyi; Liu, Yanqiu; Gao, Haichun; Yu, Zhiliang
• Is Part Of: FEMS microbiology letters. Volume 367:Issue 3(2020)
• Publication Date: 2020-02-10
• Subjects: Peptidoglycan -- Penicillin binding protein -- Cell morphology -- Envelope integrity -- Shewanella oneidensis; Microbiology -- Periodicals; 579
• DOI: 10.1093/femsle/fnaa026
• Languages: English
• ISSNs: 0378-1097

Abstract

ABSTRACT: In rod-shaped Gram-negative bacteria, penicillin binding protein 1a (PBP1a) and 1b (PBP1b) form peptidoglycan-synthesizing complexes with the outer membrane lipoprotein LpoA and LpoB, respectively. Escherichia coli mutants lacking PBP1b/LpoB are sicker than those lacking PBP1a/LpoA. However, we previously found that mutants lacking PBP1a/LpoA but not PBP1b/LpoB are deleterious in Shewanella oneidensis . Here, we show that S. oneidensis PBP1a ( So PBP1a) contains conserved signature motifs with its E. coli counterpart, Ec PBP1a. Although Ec PBP1a play a less prominent role in E. coli, it is capable of substituting for the So PBP1a in a manner dependent on So LpoA. In S. oneidensis, expression of PBP1b is lower than PBP1a, and therefore the additional expression of So PBP1b at low levels can functionally compensate for the absence of So PBP1a. Importantly, S. oneidensis PBP1a variants lacking either glycosyltransferase (GTase) or transpeptidase (TPase) activity fail to maintain normal morphology and cell envelope integrity. Similarly, So PBP1b variants also fail to compensate for the loss of So PBP1a. Furthermore, overproduction of variants of So PBP1a, but not So PBP1b, has detrimental effects on cell morphology in S. oneidensis wild type cells. Overall, our results indicate that the combined enzymatic activities of So PBP1a are essential for cell wall homeostasis. Abstract : The combined enzymatic activities of glycosyltransferase and transpeptidase are essential for cell wall homeostasis.