Protein Family Models

Cytochrome P450s are haem-thiolate proteins [6] involved in the oxidative degradation of various compounds. They are particularly well known for their role in the degradation of environmental toxins and mutagens. They can be divided into 4 classes, according to the method by which electrons from NAD(P)H are delivered to the catalytic site. Sequence conservation is relatively low within the family - there are only 3 absolutely conserved residues - but their general topography and structural fold are highly conserved. The conserved core is composed of a coil termed the 'meander', a four-helix bundle, helices J and K, and two sets of beta-sheets. These constitute the haem-binding loop (with an absolutely conserved cysteine that serves as the 5th ligand for the haem iron), the proton-transfer groove and the absolutely conserved EXXR motif in helix K. While prokaryotic P450s are soluble proteins, most eukaryotic P450s are associated with microsomal membranes. their general enzymatic function is to catalyse regiospecific and stereospecific oxidation of non-activated hydrocarbons at physiological temperatures [6]. [1]. 7549871. A three-dimensional model of aromatase cytochrome P450. Graham-Lorence S, Amarneh B, White RE, Peterson JA, Simpson ER;. Protein Sci 1995;4:1065-1080. [2]. 8405421. Molecular evolution of P450 superfamily and P450-containing monooxygenase systems. Degtyarenko KN, Archakov AI;. FEBS Lett 1993;332:1-8. [3]. 7678494. The P450 superfamily: update on new sequences, gene mapping, accession numbers, early trivial names of enzymes, and nomenclature. Nelson DR, Kamataki T, Waxman DJ, Guengerich FP, Estabrook RW, Fe. TRUNCATED at 1650 bytes (from Pfam)

Date:

2024-10-16