肺炎克雷伯菌
微生物学
克雷伯菌
酶
病菌
活动站点
化学
毒力
结合位点
细菌胶囊
生物化学
生物
大肠杆菌
基因
作者
Flavia Squeglia,Barbara Maciejewska,Agnieszka Łątka,Alessia Ruggiero,Yves Briers,Zuzanna Drulis‐Kawa,Rita Berisio
出处
期刊:Structure
[Elsevier]
日期:2020-06-01
卷期号:28 (6): 613-624.e4
被引量:47
标识
DOI:10.1016/j.str.2020.04.015
摘要
Capsule polysaccharide is a major virulence factor of Klebsiella pneumoniae, a nosocomial pathogen associated with a wide range of infections. It protects bacteria from harsh environmental conditions, immune system response, and phage infection. To access cell wall-located receptors, some phages possess tailspike depolymerases that degrade the capsular polysaccharide. Here, we present the crystal structure of a tailspike against Klebsiella, KP32gp38, whose primary sequence shares no similarity to other proteins of known structure. In the trimeric structure of KP32gp38, each chain contains a flexible N-terminal domain, a right-handed parallel β helix domain and two β sandwiches with carbohydrate binding features. The crystal structure and activity assays allowed us to locate the catalytic site. Also, our data provide experimental evidence of a branching architecture of depolymerases in KP32 Klebsiella viruses, as KP32gp38 displays nanomolar affinity to another depolymerase from the same phage, KP32gp37. Results provide a structural framework for enzyme engineering to produce serotype-broad-active enzyme complexes against K. pneumoniae.
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