TAILIEUCHUNG - Báo cáo khóa học: Volkensin from Adenia volkensii Harms (kilyambiti plant), a type 2 ribosome-inactivating protein

Volkensin, a type 2 ribosome-inactivating protein from the roots of Adenia volkensiiHarms (kilyambiti plant) was characterized both at the protein and nucleotide level by direct amino acid sequencing and cloning of the gene enco-ding the protein. Gene sequence analysis revealed that vol-kensin is encoded by a 1569-bp ORF (523 amino acid residues) without introns, withan internal linker sequence of 45 bp. Differences in residues present at several sequence positions (reproduced after repeated protein sequence ana-lyses), with respect to the gene sequence, suggest several isoforms for the volkensin A-chain | Eur. J. Biochem. 271 108-117 2004 FEBS 2003 doi Volkensin from Adenia volkensii Harms kilyambiti plant a type 2 ribosome-inactivating protein Gene cloning expression and characterization of its A-chain Angela Chambery1 Antimo Di Maro1 Maurilia M. Monti2 Fiorenzo Stirpe3 and Augusto Parente1 1 Dipartimento di Scienze della Vita Seconda Universita di Napoli Caserta Italy 2Istituto per la Protezione delle Piante CNR Sezione di Portici Portici Na Italy 3Dipartimento di Patologia Sperimentale Universita di Bologna Bologna Italy Volkensin a type 2 ribosome-inactivating protein from the roots of Adenia volkensii Harms kilyambiti plant was characterized both at the protein and nucleotide level by direct amino acid sequencing and cloning of the gene encoding the protein. Gene sequence analysis revealed that vol-kensin is encoded by a 1569-bp ORF 523 amino acid residues without introns with an internal linker sequence of 45 bp. Differences in residues present at several sequence positions reproduced after repeated protein sequence analyses with respect to the gene sequence suggest several isoforms for the volkensin A-chain. Based on the crystallographic coordinates of ricin which shares a high sequence identity with volkensin a molecular model of volkensin was obtained. The 3D model suggests that the amino acid residues of the active site of the ricin A-chain are conserved at identical spatial positions including Ser203 a novel amino acid residue found to be conserved in all known ribosomeinactivating proteins. The sugar binding site 1 of the ricin B-chain is also conserved in the volkensin B-chain whilst in binding site 2 His246 replaces Tyr248. Native volkensin contains two free cysteinyl residues out of 14 derived from the gene sequence thus suggesting a further disulphide bridge in the B chain in addition to the inter- and intrachain disulphide bond pattern common to other type 2 ribosomeinactivating proteins. Keywords .

• Báo cáo khoa học
• Report medicine
• traditional medicine
• scientific reports
• medical knowledge
• cytoplasm
• analysis of cytoplasmic
• medical research
• oxidation
• Crystal structure
• bacteria
• hemoglobin
• medicine
• cell proliferation
• breast cancer
• chemical reaction
• gastric cancer
• hormone medicine
• tumor cells
• biochemical studies
• environmental medicine