کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1317207 976514 2007 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Roles of distal arginine in activity and stability of Coprinus cinereus peroxidase elucidated by kinetic and NMR analysis of the Arg51Gln, -Asn, -Leu, and -Lys mutants
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی معدنی
پیش نمایش صفحه اول مقاله
Roles of distal arginine in activity and stability of Coprinus cinereus peroxidase elucidated by kinetic and NMR analysis of the Arg51Gln, -Asn, -Leu, and -Lys mutants
چکیده انگلیسی

In heme peroxidases, a distal His residue plays an essential role in the initial two electron oxidation of resting state enzyme to compound I by hydrogen peroxide. A distal Arg residue assists in this process. The contributions of the charge, H-bonding capacity, size, and mobility of this Arg residue to Coprinus cinereus peroxidase (CIP) reactivity and stability have been examined by substituting Arg51 with Gln (retains H-bond donor at Nε position), Asn (small size, H-bond donor and acceptor), Leu (similar to Asn, but hydrophobic), and Lys (charge and H-bond donor, but at Nζ position). UV–visible spectroscopy was used to monitor pH-linked heme changes, compound I formation and reduction, fluoride binding, and thermostability. 1H NMR spectroscopy enabled heme pocket differences in both resting and cyanide-ligated states of the enzymes to be evaluated and compared with wild-type CIP. We found that the H-bonding capacity of distal Arg is key to fast compound I formation and ligand binding to heme, whereas charge is important for lowering the pKa of distal His and for the binding and stabilisation of anionic ligands at heme iron. The properties of the distal Arg residue in CIP, cytochrome c peroxidase (CCP) and horseradish peroxidase (HRP) differ significantly in their pH induced transitions and dynamics.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Inorganic Biochemistry - Volume 101, Issue 2, February 2007, Pages 336–347
نویسندگان
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