TAILIEUCHUNG - Báo cáo Y học: Thiol-modifying inhibitors for understanding squalene cyclase function

The function of squalene-hopene cyclase from Alicyclobacillus acidocaldarius was studied by labelling critical cysteine residues of the enzyme, either native or inserted by sitedirected mutagenesis, with different thiol-reacting molecules. The access of the substrate to the active centre cavity through a nonpolar channel that contains a narrow constriction harbouring a cysteine residue (C435) was probed by labelling experiments on both a C435S mutant, lacking C435 of the channel constriction, and a C25S/C50S/C455S/C537S mutant, bearing C435 as the only cysteine residue. Labelling experiments with tritiated 3-carboxy-4-nitrophenyl-dithio1,1¢,2-trisnorsqualene (CNDT-squalene) showed that the cysteine residue at the channel constriction was covalently modified by the. | Eur. J. Biochem. 269 2108-2116 2002 FEBS 2002 doi Thiol-modifying inhibitors for understanding squalene cyclase function Paola Milla1 Alexander Lenhart2 Giorgio Grosa3 Franca Viola1 Wilhelm A. Weihofen2 Georg E. Schulz2 and Gianni Balliano1 1Universita degli Studi di Torino Dipartimento di Scienza e Tecnologia del Farmaco Torino Italy 2Universitdt Freiburg Institut fur Organische Chemie und Biochemie Freiburg Germany U niversila degli Studi del Piemonte Orientale A. Avogadro Dipartimento di Scienze Chimiche Alimentari Farmaceutiche e Farmacologiche Novara Italy The function of squalene-hopene cyclase from Alicycloba-cillus acidocaldarius was studied by labelling critical cysteine residues of the enzyme either native or inserted by site-directed mutagenesis with different thiol-reacting molecules. The access of the substrate to the active centre cavity through a nonpolar channel that contains a narrow constriction harbouring a cysteine residue C435 was probed by labelling experiments on both a C435S mutant lacking C435 of the channel constriction and a C25S C50S C455S C537S mutant bearing C435 as the only cysteine residue. Labelling experiments with tritiated 3-carboxy-4-nitrophenyl-dithio-1 1 2-trisnorsqualene CNDT-squalene showed that the cysteine residue at the channel constriction was covalently modified by the squalene-like inhibitor. Time-dependent inactivation of the C25S C50S C455S C537S mutant by a number of squalene analogues and other agents with thiol-modifying activity suggested that modifying C435 caused the obstruction of the channel constriction thus blocking access of the substrate to the active site. The tryptic fragment comprising C435 of the quadruple mutant labelled with the most effective inhibitor had the expected altered molecular mass as determined by LC-ESI-MS measurements. The arrangement of the substrate in the active site cavity was studied by using thiol reagents as probes in labelling experiments with .

• Báo cáo khoa học
• Traditional medicine
• Report medicine
• scientific reports
• medical knowledge
• cytoplasm
• analysis of cytoplasmic
• Commercial use
• Tadehagi triquetrum (L ) H Ohashi
• Indigenous medicine in Myanmar
• Medicinal plants
• Calotropis gigantea R
• Br
• Traditional medicinal plants
• Local development in Myanmar
• Important role in health care system
• BMC Chemistry
• Trace analysis
• Dispersive solvent
• Traditional Chinese medicine
• Chinese medicine oral liquid
• Veterinary Medicine
• Herbal Medicine
• Varughese George
• Andrographis paniculata
• Chemical Constituents
• alternative medicine
• diagnostic techniques
• Diagnostic therapies
• Chinese medicine
• Medical herbalism
• Massage therapy review
• Lecture Massage therapy review
• Bodywork assessment
• Massage therapy
• Traditional chinese medicine modality
• Acanthospermum hispidum
• Burkina faso
• Pharmacognosic characterization
• Acanthospermum hispidum (Asteraceae)
• Medicinal plant widely
• Active components
• Plasma protein binding
• Research methods
• Doctoral thesis abstract
• Improving accounting work organization
• Accounting work organization
• Traditional medicine hospitals
• Hanoi city
• Vietnamese traditional medicine
• Medicinal herbs
• Ethnic groups
• Community healthcare
• Mountainous area
• Cultural Perspective
• Modern Medicine
• Funding Perspective
• Traditional Oriental
• medicine
• cell proliferation
• oxidation
• breast cancer
• chemical reaction
• gastric cancer
• hormone medicine
• tumor cells
• biochemical studies
• environmental medicine
• Crystal structure