TAILIEUCHUNG - Báo cáo khoa học: The structure of maize polyamine oxidase K300M mutant in complex with the natural substrates provides a snapshot of the catalytic mechanism of polyamine oxidation

Polyamine oxidases are FAD-dependent enzymes catalyzing the oxidation of polyamines at the secondary amino maysPAO (ZmPAO) oxidizes the carbon on the endo-side of the N5-nitrogen of spermidine (Spd) and spermine (Spm). | IFEBS Journal The structure of maize polyamine oxidase K300M mutant in complex with the natural substrates provides a snapshot of the catalytic mechanism of polyamine oxidation Annarita Fiorillo1 2 Rodolfo Federico3 Fabio Polticelli3 Alberto Boffi2 Franco Mazzei4 Massimo Di Fusco4 Andrea Ilari2 and Paraskevi Tavladoraki3 1 Department of Science and BiomedicalTechnology University of L Aquila Italy 2 CNR Institute of Molecular Biology and Pathology and Department of BiochemicalSciences Sapienza University of Rome Italy 3 Department of Biology University Roma Tre Rome Italy 4 Department of Chemistry and Drug Technologies Sapienza University of Rome Italy Keywords K300M mutant spermidine spermine X-ray structures Zea mays polyamine oxidase Correspondence A. Ilari IBPM-CNR c o Department of Biochemical Sciences University of Rome Sapienza A. Moro 5 00185 Rome Italy Fax 39 064 440 062 Tel 39 064 991 0990 E-mail Received 1 July 2010 revised 17 December 2010 accepted 23 December 2010 doi Polyamine oxidases are FAD-dependent enzymes catalyzing the oxidation of polyamines at the secondary amino groups. Zea mays PAO ZmPAO oxidizes the carbon on the endo-side of the N5-nitrogen of spermidine Spd and spermine Spm . The structure of ZmPAO revealed that the active site is formed by a catalytic tunnel in which the N5 atom of FAD lies in close proximity to the K300 side chain the only active-site residue conserved in all PAOs. A water molecule HOH309 is hydrogen-bound to the amino group of K300 and mutation of this residue results in a 1400fold decrease in the rate of flavin reduction. The structural studies on the catalytically impaired ZmPAO-K300M mutant described here show that substrates are bound in an out-of-register mode and the HOH309 water molecule is absent in the enzyme-substrate complexes. Moreover K300 mutation brings about a 60 mV decrease in the FAD redox potential and a 30-fold decrease in the FAD .

TỪ KHÓA 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.