A conserved zinc-binding site in Acinetobacter baumannii PBP2 required for elongasome-directed bacterial cell shape.
A conserved zinc-binding site in Acinetobacter baumannii PBP2 required for elongasome-directed bacterial cell shape.
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DOI：
10.1073/pnas.2215237120
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发表时间：
2023-02-21
影响因子：
11.1
通讯作者：
Roper, David I.
中科院分区：
文献类型：
--
作者：
Micelli, Carmina;Dai, Yunfei;Raustad, Nicole;Isberg, Ralph R.;Dowson, Christopher G.;Lloyd, Adrian J.;Geisinger, Edward;Crow, Allister;Roper, David I.
鲍曼不动杆菌是一种与医院获得性感染相关的机会性革兰氏阴性细菌病原体，而碳青霉烯类耐药菌株带来了特别严重的生物医学威胁。在这里，我们发现 PBP2 是负责细菌细胞形状的主要酶，也是二氮杂双环辛烷 (DBO) 类 β-内酰胺酶抑制剂的靶标，它在转肽酶结构域中拥有一个值得注意的锌结合位点。破坏锌协调的基因突变会阻碍功能互补，从而导致体内功能丧失。这些结果为鲍曼不动杆菌细胞代谢和形状决定中锌的需求提供了理论依据，为未来对抗不动杆菌感染的抗菌策略提供了前景。鲍曼不动杆菌是一种革兰氏阴性细菌病原体，可引起具有挑战性的医院感染。 β-内酰胺靶向青霉素结合蛋白 (PBP) 介导的细胞壁肽聚糖 (PG) 形成是一种成熟的抗菌策略。暴露于碳青霉烯类或缺乏锌 (Zn) 的生长条件会导致鲍曼不动杆菌发生棒状到球状的形态转变，这种效应类似于细胞壁伸长所需的 RodA-PBP2 PG 合成复合物缺陷引起的效应。虽然人们认识到碳青霉烯类优先酰化鲍曼不动杆菌中的 PBP2，从而阻断 RodA-PBP2 系统的转肽酶功能，但支持 Zn 饥饿时细胞壁伸长抑制的分子细节仍不清楚。在这里，我们报告了鲍曼不动杆菌 PBP2 的 X 射线晶体结构，揭示了蛋白质稳定性所需的转肽酶结构域中意想不到的 Zn 配位位点。 PBP2 锌结合位点的突变导致细菌杆状形状的丧失并增加对 β-内酰胺的敏感性，因此为鲍曼不动杆菌中细胞壁形状的维持和锌稳态提供了直接的原理。此外，Zn 配位残基在各种 β- 和 γ- 变形菌 PBP2 直向同源物中是保守的，这与以前未知的广泛的 Zn 结合功能要求一致。由于几乎所有市售抗生素类别都出现了耐药性，因此需要探索替代或补充的抗菌策略。这些发现为金属螯合剂双重抑制 Zn 依赖性 PG 合酶和金属-β-内酰胺酶提供了前景，金属螯合剂被认为是恢复 β-内酰胺对抗革兰氏阴性菌效力的最受欢迎的佐剂。
Acinetobacter baumannii is an opportunistic gram-negative bacterial pathogen associated with hospital-acquired infections, and carbapenem-resistant strains present a particularly acute biomedical threat. Here, we show that PBP2, which is the major enzyme responsible for bacterial cell shape and a target for the diazabicyclooctane (DBO) class of β-lactamase inhibitors, holds a noteworthy zinc-binding site in the transpeptidase domain. Gene mutations that disrupt Zn coordination prevent functional complementation consistent with loss of function in vivo. These results provide a rationale for the requirements of zinc in cellular metabolism and shape determination in Acinetobacter baumannii, offering a perspective for future antimicrobial strategies to combat Acinetobacter infections. Acinetobacter baumannii is a gram-negative bacterial pathogen that causes challenging nosocomial infections. β-lactam targeting of penicillin-binding protein (PBP)–mediated cell wall peptidoglycan (PG) formation is a well-established antimicrobial strategy. Exposure to carbapenems or zinc (Zn)-deprived growth conditions leads to a rod-to-sphere morphological transition in A. baumannii, an effect resembling that caused by deficiency in the RodA–PBP2 PG synthesis complex required for cell wall elongation. While it is recognized that carbapenems preferentially acylate PBP2 in A. baumannii and therefore block the transpeptidase function of the RodA–PBP2 system, the molecular details underpinning cell wall elongation inhibition upon Zn starvation remain undefined. Here, we report the X-ray crystal structure of A. baumannii PBP2, revealing an unexpected Zn coordination site in the transpeptidase domain required for protein stability. Mutations in the Zn-binding site of PBP2 cause a loss of bacterial rod shape and increase susceptibility to β-lactams, therefore providing a direct rationale for cell wall shape maintenance and Zn homeostasis in A. baumannii. Furthermore, the Zn-coordinating residues are conserved in various β- and γ-proteobacterial PBP2 orthologs, consistent with a widespread Zn-binding requirement for function that has been previously unknown. Due to the emergence of resistance to virtually all marketed antibiotic classes, alternative or complementary antimicrobial strategies need to be explored. These findings offer a perspective for dual inhibition of Zn-dependent PG synthases and metallo-β-lactamases by metal chelating agents, considered the most sought-after adjuvants to restore β-lactam potency against gram-negative bacteria.
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影响因子：
6.4
作者：
Dai Y;Pinedo V;Tang AY;Cava F;Geisinger E
通讯作者：
Geisinger E
DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
5.6
作者：
Fedarovich, Alena;Nicholas, Robert A.;Davies, Christopher
通讯作者：
Davies, Christopher
DOI：
10.1107/s090744490903947x
发表时间：
2010-04
期刊：
Acta crystallographica. Section D, Biological crystallography
影响因子：
--
作者：
Cowtan K
通讯作者：
Cowtan K
影响因子：
8.8
作者：
Brazel, Erin B.;Tan, Aimee;Neville, Stephanie L.;Iverson, Amy R.;Udagedara, Saumya R.;Cunningham, Bliss A.;Sikanyika, Mwilye;De Oliveira, David M. P.;Keller, Bernhard;Bohlmann, Lisa;El-Deeb, Ibrahim M.;Ganio, Katherine;Eijkelkamp, Bart A.;McEwan, Alastair G.;von Itzstein, Mark;Maher, Megan J.;Walker, Mark J.;Rosch, Jason W.;McDevitt, Christopher A.
通讯作者：
McDevitt, Christopher A.