tailieunhanh - Báo cáo khoa học: Solution structure of the catalytic domain of RICH protein from goldfish

Regeneration-induced CNPase homolog (RICH) is an axonal growth-associated protein, which is induced in teleost fish upon optical nerve injury. RICH consists of a highly acidic N-terminal domain, a catalytic domain with 2¢,3¢-cyclic nucleotide 3¢-phosphodiesterase (CNPase) activity and a C-terminal isoprenylation site. | ễFEBS Journal Solution structure of the catalytic domain of RICH protein from goldfish Guennadi Kozlov Alexey Y. Denisov Ekaterina Pomerantseva Michel Gravel Peter E. Braun and Kalle Gehring Department of Biochemistry McGillUniversity Montreal Quebec Canada Keywords CNPase 2H phosphoesterase superfamily NMR solution structure RICH protein tRNA splicing Correspondence K. Gehring Department of Biochemistry McGillUniversity 3655 Promenade Sir William Osler Montreal Quebec Canada H3G 1Y6 Fax 1 514 3987384 Tel 1 514 3987287 E-mail Website http biochemistry department faculty gehring Received 6 December 2006 revised 16 January 2007 accepted 17 January 2007 doi Regeneration-induced CNPase homolog RICH is an axonal growth-associated protein which is induced in teleost fish upon optical nerve injury. RICH consists of a highly acidic N-terminal domain a catalytic domain with 2 3 -cyclic nucleotide 3 -phosphodiesterase CNPase activity and a C-terminal isoprenylation site. In vitro RICH and mammalian brain CNPase specifically catalyze the hydrolysis of 2 3 -cyclic nucleotides to produce 2 -nucleotides but the physiologically relevant in vivo substrate remains unknown. Here we report the NMR structure of the catalytic domain of goldfish RICH and describe its binding to CNPase inhibitors. The structure consists of a twisted nine-stranded antiparallel b-sheet surrounded by a-helices on both sides. Despite significant local differences mostly arising from a seven-residue insert in the RICH sequence the active site region is highly similar to that of human CNPase. Likewise refinement of the catalytic domain of rat CNPase using residual dipolar couplings gave improved agreement with the published crystal structure. NMR titrations of RICH with inhibitors point to a similar catalytic mechanism for RICH and CNPase. The results suggest a functional importance for the evo-lutionarily conserved phosphodiesterase .