tailieunhanh - Báo cáo khoa học: New insights into the functions and N-glycan structures of factor X activator from Russell’s viper venom

The coagulation factor X activator from Russell’s viper venom (RVV-X) is a heterotrimeric glycoprotein. In this study, its three subunits were cloned and sequenced from the venom gland cDNAs of Daboia siamensis. The deduced heavy chain sequence contained a C-terminal extension with four additional residues to that published previously. | ễFEBS Journal New insights into the functions and N-glycan structures of factor X activator from Russell s viper venom Hong-Sen Chen1 Jin-Mei Chen2 Chia-Wei Lin1 Kay-Hooi Khoo1 2 and Inn-Ho Tsai1 2 1 Graduate Institute of BiochemicalSciences NationalTaiwan University Taiwan 2 Institute of BiologicalChemistry Academia Sinica Taipei Taiwan Keywords cDNA cloning factor X activator glycan mass spectrometry Lewis and sialyl-Lewis Russell s viper venom Correspondence I. H. Tsai Institute of BiologicalChemistry Academia Sinica PO Box 23-106 Taipei Taiwan Fax 886 22 3635038 Tel 886 22 3620264 E-mail bc201@ Received 18 February 2008 revised 22 April2008 accepted 5 June 2008 doi The coagulation factor X activator from Russell s viper venom RVV-X is a heterotrimeric glycoprotein. In this study its three subunits were cloned and sequenced from the venom gland cDNAs of Daboia siamensis. The deduced heavy chain sequence contained a C-terminal extension with four additional residues to that published previously. Both light chains showed 77-81 identity to those of a homologous factor X activator from Vipera lebetina venom. Far-western analyses revealed that RVV-X could strongly bind protein S in addition to factors X and IX. This might inactivate protein S and potentiate the disseminated intravascular coagulation syndrome elicited by Russell s viper envenomation. The N-glycans released from each subunit were profiled and sequenced by MALDI-MS and MS MS analyses of the permethyl derivatives. All the glycans one on each light chain and four on the heavy chain showed a heterogeneous pattern with a combination of variable terminal fucosylation and sialylation on multiantennary complex-type sugars. Amongst the notable features were the presence of terminal Lewis and sialyl-Lewis epitopes as confirmed by western blotting analyses. As these glyco-epitopes have specific receptors in the vascular system they possibly contribute to the .