کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5506681 1400301 2016 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Crystal structure of the ADP-ribosylating component of BEC, the binary enterotoxin of Clostridium perfringens
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
Crystal structure of the ADP-ribosylating component of BEC, the binary enterotoxin of Clostridium perfringens
چکیده انگلیسی


- We determined the crystal structure of the ADP-ribosylating subunit BECa of a novel binary enterotoxin of C. perfringens.
- The substrate-binding mechanisms of BECa, including implications for the molecular recognition of actin, were presented.
- The conformational change of the ADP-ribosylating turn-turn loop coupled with substrate binding plays a crucial role in catalysis by BECa.

Binary enterotoxin of Clostridium perfringens (BEC), consisting of the components BECa and BECb, was recently identified as a novel enterotoxin produced by C. perfringens that causes acute gastroenteritis in humans. Although the detailed mechanism of cell intoxication by BEC remains to be defined, BECa shows both NAD+-glycohydrolase and actin ADP-ribosyltransferase activities in the presence of NAD+. In this study, we determined the first crystal structure of BECa in its apo-state and in complex with NADH. The structure of BECa shows striking resemblance with other binary actin ADP-ribosylating toxins (ADPRTs), especially in terms of its overall protein fold and mechanisms of substrate recognition. We present a detailed picture of interactions between BECa and NADH, including bound water molecules located near the C1′-N glycosidic bond of NADH and the catalytically important ADP-ribosylating turn-turn (ARTT) loop. We observed that the conformational rearrangement of the ARTT loop, possibly triggered by a conformational change involving a conserved tyrosine residue coupled with substrate binding, plays a crucial role in catalysis by properly positioning a catalytic glutamate residue in the E-X-E motif of the ARTT loop in contact with the nucleophile. Our results for BECa provide insight into the common catalytic mechanism of the family of binary actin ADPRTs.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochemical and Biophysical Research Communications - Volume 480, Issue 2, 11 November 2016, Pages 261-267
نویسندگان
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