TAILIEUCHUNG - Báo cáo khoa học: Structure and function of N-acetylglucosamine kinase Identification of two active site cysteines

N-Acetylglucosamine is a major component of com-plex carbohydrates. The mammalian salvage pathway of N-acetylglucosamine recruitment from glycoconjugate deg-radation or nutritional sources starts with phosphorylation byN-acetylglucosamine kinase. In this studywe describe the identification of two active site cysteines of the sugar kinase by site-directed mutagenesis and computer-based structure prediction. | Eur. J. Biochem. 269 4212-4218 2002 FEBS 2002 doi Structure and function of V-acetylglucosamine kinase Identification of two active site cysteines Markus Berger Hao Chen Werner Reutter and Stephan Hinderlich Institut fur Molekularbiologie und Biochemie Freie Universitat Berlin Berlin-Dahlem Germany N-Acetylglucosamine is a major component of complex carbohydrates. The mammalian salvage pathway of N-acetylglucosamine recruitment from glycoconjugate degradation or nutritional sources starts with phosphorylation by N-acetylglucosamine kinase. In this study we describe the identification of two active site cysteines of the sugar kinase by site-directed mutagenesis and computer-based structure prediction. Murine N-acetylglucosamine kinase contains six cysteine residues al 1 of which were mtitled to serine residues. The strongest reduction of enzyme activity was found for the mutant C131S I olkweal yy C14SS. Dtter-mination of the kinetic properties of the cysteine mutants showed that the decreased enzyme activities were due to a strongly decreased affinity to either N-acntylglucosamine for C131S or ATPforC143S. A l c sn eken l lleKỊtLrn ls eiCỊir m of N-acetylglucosamine kinase showed a high homology to glucokinase. A model of the three-dimensional structure of N-acetylglucosamine kinase based on the known structure of glucokinase was therefore generated. This model confirmed that both cysteines are located in the active site of N-acetylglucosamine kinase with a potential role in the binding of the transfered y-phosphate group of ATP within the catalytic mechanism. Keywords N-acntylglucosamine kinase N-acntylglucos-amine aminosugar metabolism ATP binding domain cysteine residue. N-Acntylglucosamine kinase GlcNAc kinase EC catalyzes the phosphorylation of N-acetylglucosamine GlcNAc to GlcNAc 6-phosphate. GlcNAc rrom lyso--omal degradation of oligosaccharides or nutritional sources is a mum subtlTine or the cynthyeis df E DP-GceN .

TÀI LIỆU LIÊN QUAN
Đã phát hiện trình chặn quảng cáo AdBlock
Trang web này phụ thuộc vào doanh thu từ số lần hiển thị quảng cáo để tồn tại. Vui lòng tắt trình chặn quảng cáo của bạn hoặc tạm dừng tính năng chặn quảng cáo cho trang web này.