Assignment of haem ligands and detection of electronic absorption bands of molybdenum in the di-haem periplasmic nitrate reductase of Paracoccus pantotrophus

Butler, Clive S., Ferguson, Stuart J., Berks, Ben C., Thomson, Andrew J., Cheesman, Myles R. and Richardson, David J. ORCID: https://orcid.org/0000-0002-6847-1832 (2002) Assignment of haem ligands and detection of electronic absorption bands of molybdenum in the di-haem periplasmic nitrate reductase of Paracoccus pantotrophus. FEBS Letters, 500 (1-2). pp. 71-74. ISSN 1873-3468

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Abstract

The periplasmic nitrate reductase (NAP) from Paracoccus pantotrophus is a soluble two-subunit enzyme (NapAB) that binds two c-type haems, a [4Fe–4S] cluster and a bis-molybdopterin guanine dinucleotide cofactor that catalyses the reduction of nitrate to nitrite. In the present work the NapAB complex has been studied by magneto-optical spectroscopy to probe co-ordination of both the NapB haems and the NapA active site Mo. The absorption spectrum of the NapAB complex is dominated by features from the NapB c-type cytochromes. Using a combination of electron paramagnetic resonance spectroscopy and magnetic circular dichroism it was demonstrated that both haems are low-spin with bis-histidine axial ligation. In addition, a window between 600 and 800 nm was identified in which weak absorption features that may arise from Mo could be detected. The low-temperature MCD spectrum shows oppositely signed bands in this region (peak 648 nm, trough 714 nm) which have been assigned to S-to-Mo(V) charge transfer transitions.

Item Type:	Article
Faculty \ School:	Faculty of Science > School of Biological Sciences
UEA Research Groups:	Faculty of Science > Research Groups > Chemistry of Light and Energy Faculty of Science > Research Groups > Chemistry of Life Processes Faculty of Science > Research Centres > Centre for Molecular and Structural Biochemistry Faculty of Science > Research Groups > Organisms and the Environment Faculty of Science > Research Groups > Molecular Microbiology
Depositing User:	EPrints Services
Date Deposited:	01 Oct 2010 13:37
Last Modified:	24 Sep 2024 10:15
URI:	https://ueaeprints.uea.ac.uk/id/eprint/556
DOI:	10.1016/S0014-5793(01)02577-7

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