Faculty Collaboration Database

Bacterial Renalase: Structure and Kinetics of an Enzyme with 2- and 6-Dihydro-β-NAD(P) Oxidase Activity from Pseudomonas phaseolicola. Biochemistry 2015 Jun 23;54(24):3791-802

Date

05/29/2015

Pubmed ID

26016690

DOI

10.1021/acs.biochem.5b00451

Scopus ID

2-s2.0-84934954581 (requires institutional sign-in at Scopus site)   18 Citations

Abstract

Despite a lack of convincing in vitro evidence and a number of sound refutations, it is widely accepted that renalase is an enzyme unique to animals that catalyzes the oxidative degradation of catecholamines in blood in order to lower vascular tone. Very recently, we identified isomers of β-NAD(P)H as substrates for renalase (Beaupre, B. A. et al. (2015) Biochemistry, 54, 795-806). These molecules carry the hydride equivalent on the 2 or 6 position of the nicotinamide base and presumably arise in nonspecific redox reactions of nicotinamide dinucleotides. Renalase serves to rapidly oxidize these isomers to form β-NAD(P)⁺ and then pass the electrons to dioxygen, forming H₂O₂. We have also shown that these substrate molecules are highly inhibitory to dehydrogenase enzymes and thus have proposed an intracellular metabolic role for this enzyme. Here, we identify a renalase from an organism without a circulatory system. This bacterial form of renalase has the same substrate specificity profile as that of human renalase but, in terms of binding constant (K(d)), shows a marked preference for substrates derived from β-NAD⁺. 2-dihydroNAD(P) substrates reduce the enzyme with rate constants (k(red)) that greatly exceed those for 6-dihydroNAD(P) substrates. Taken together, k(red)/K(d) values indicate a minimum 20-fold preference for 2DHNAD. We also offer the first structures of a renalase in complex with catalytically relevant ligands β-NAD⁺ and β-NADH (the latter being an analogue of the substrate(s)). These structures show potential electrostatic repulsion interactions with the product and a unique binding orientation for the substrate nicotinamide base that is consistent with the identified activity.

Author List

Hoag MR, Roman J, Beaupre BA, Silvaggi NR, Moran GR

Author

Nicholas R. Silvaggi PhD Assistant Professor in the Chemistry and Biochemistry department at University of Wisconsin - Milwaukee

MESH terms used to index this publication - Major topics in bold

Bacterial Proteins
Biocatalysis
Catalytic Domain
Computer Simulation
Humans
Ligands
Models, Molecular
Molecular Conformation
Monoamine Oxidase
NAD
NADP
NADPH Oxidases
Oxidation-Reduction
Protein Conformation
Pseudomonas
Recombinant Proteins
Stereoisomerism
Substrate Specificity