3HUI

Crystal Structure of the mutant A105R of [2Fe-2S] Ferredoxin in the Class I CYP199A2 System from Rhodopseudomonas palustris

Summary for 3HUI

• Entry DOI: 10.2210/pdb3hui/pdb
• Related: 2FR7 3FG2
• Descriptor: Ferredoxin, FE2/S2 (INORGANIC) CLUSTER (3 entities in total)
• Functional Keywords: cytochrome p450, ferredoxin, rhodopseudomonas palustris, electron transfer, iron, iron-sulfur, metal-binding, electron transport
• Biological source: Rhodopseudomonas palustris
• Total number of polymer chains: 1
• Total formula weight: 13933.18

Authors

Bell, S.G.,Xu, F.,Rao, Z.,Wong, L.-L. (deposition date: 2009-06-14, release date: 2010-02-09, Last modification date: 2023-11-01)

Primary citation

Bell, S.G.,Xu, F.,Johnson, E.O.,Forward, I.M.,Bartlam, M.,Rao, Z.,Wong, L.L.
Protein recognition in ferredoxin-P450 electron transfer in the class I CYP199A2 system from Rhodopseudomonas palustris
J.Biol.Inorg.Chem., 15:315-328, 2010

PubMed Abstract: CYP199A2 from Rhodopseudomonas palustris CGA009 is a heme monooxygenase that catalyzes the oxidation of para-substituted benzoic acids. CYP199A2 activity is reconstituted by a class I electron transfer chain consisting of the associated [2Fe-2S] ferredoxin palustrisredoxin (Pux) and a flavoprotein palustrisredoxin reductase (PuR). Another [2Fe-2S] ferredoxin, palustrisredoxin B (PuxB; RPA3956) has been identified in the genome. PuxB shares sequence identity and motifs with vertebrate-type ferredoxins involved in Fe-S cluster assembly but also 50% identity with Pux and it mediates electron transfer from PuR to CYP199A2, albeit with lower steady-state turnover activity: 99 nmol (nmol P450)(-1)min(-1) for 4-methoxybenzoic acid oxidation compared with 1,438 nmol (nmol P450)(-1 )min(-1) for Pux. This difference mainly arises from weak CYP199A2-PuxB binding (K (m) 34.3 vs. 0.45 microM for Pux) rather than slow electron transfer (k (cat) 19.1 vs. 37.9 s(-1) for Pux). Comparison of the 2.0-A-resolution crystal structure of the PuxB A105R mutant with other vertebrate-type, P450-associated ferredoxins revealed similar protein folds but also significant differences in some loop regions. Therefore, PuxB offers a platform for studying ferredoxin-P450 recognition in class I P450 systems. Substitution of PuxB residues at key locations with those in Pux shows that Ala42, Cys43, and Ala44 in the [2Fe-2S] cluster binding loop and Met66 are important in electron transfer from PuxB to CYP199A2, whereas Phe73 and the C-terminal Ala105 were involved in both protein binding and electron transfer.

PubMed: 19904564
DOI: 10.1007/s00775-009-0604-7

Experimental method

X-RAY DIFFRACTION (2.01 Å)