کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1317575 976546 2007 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Modification of the active site of Mycobacterium tuberculosis KatG after disruption of the Met–Tyr–Trp cross-linked adduct
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی معدنی
پیش نمایش صفحه اول مقاله
Modification of the active site of Mycobacterium tuberculosis KatG after disruption of the Met–Tyr–Trp cross-linked adduct
چکیده انگلیسی

Mycobacterium tuberculosis catalase-peroxidase (Mtb KatG) is a bifunctional enzyme that possesses both catalase and peroxidase activities and is responsible for the activation of the antituberculosis drug isoniazid. Mtb KatG contains an unusual adduct in its distal heme-pocket that consists of the covalently linked Trp107, Tyr229, and Met255. The KatG(Y229F) mutant lacks this adduct and has decreased steady-state catalase activity and enhanced peroxidase activity. In order to test a potential structural role of the adduct that supports catalase activity, we have used resonance Raman spectroscopy to probe the local heme environment of KatG(Y229F). In comparison to wild-type KatG, resting KatG(Y229F) contains a significant amount of 6-coordinate, low-spin heme and a more planar heme. Resonance Raman spectroscopy of the ferrous–CO complex of KatG(Y229F) suggest a non-linear Fe–CO binding geometry that is less tilted than in wild-type KatG. These data provide evidence that the Met–Tyr–Trp adduct imparts structural stability to the active site of KatG that seems to be important for sustaining catalase activity.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Inorganic Biochemistry - Volume 101, Issue 3, March 2007, Pages 422–433
نویسندگان
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