Next Article in Journal
Recent Advances in Organocatalyzed Domino C–C Bond-Forming Reactions
Next Article in Special Issue
Identification of Inhibitors Targeting Ferredoxin-NADP+ Reductase from the Xanthomonas citri subsp. citri Phytopathogenic Bacteria
Previous Article in Journal
Hot Spots for Protein Partnerships at the Surface of Cholinesterases and Related α/β Hydrolase Fold Proteins or Domains—A Structural Perspective
Previous Article in Special Issue
Activation of Recombinantly Expressed l-Amino Acid Oxidase from Rhizoctonia solani by Sodium Dodecyl Sulfate
Article Menu
Issue 1 (January) cover image

Export Article

Open AccessFeature PaperArticle
Molecules 2018, 23(1), 32; https://doi.org/10.3390/molecules23010032

Structural Basis for the Substrate Inhibition of Proline Utilization A by Proline

1
Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA
2
Department of Chemistry, University of Missouri, Columbia, MO 65211, USA
3
Department of Biochemistry, Redox Biology Center, University of Nebraska, Lincoln, NE 68588, USA
*
Author to whom correspondence should be addressed.
Received: 6 December 2017 / Revised: 19 December 2017 / Accepted: 21 December 2017 / Published: 23 December 2017
(This article belongs to the Special Issue Flavoenzymes)
View Full-Text   |   Download PDF [4329 KB, uploaded 23 December 2017]   |  

Abstract

Proline utilization A (PutA) is a bifunctional flavoenzyme that catalyzes the two-step oxidation of l-proline to l-glutamate using spatially separated proline dehydrogenase (PRODH) and l-glutamate-γ-semialdehyde dehydrogenase (GSALDH) active sites. Substrate inhibition of the coupled PRODH-GSALDH reaction by proline is a common kinetic feature of PutAs, yet the structural basis for this phenomenon remains unknown. To understand the mechanism of substrate inhibition, we determined the 2.15 Å resolution crystal structure of Bradyrhizobium japonicum PutA complexed with proline. Proline was discovered in five locations remote from the PRODH active site. Most notably, strong electron density indicated that proline bound tightly to the GSAL binding site of the GSALDH active site. The pose and interactions of proline bound in this site are remarkably similar to those of the natural aldehyde substrate, GSAL, implying that proline inhibits the GSALDH reaction of PutA. Kinetic measurements show that proline is a competitive inhibitor of the PutA GSALDH reaction. Together, the structural and kinetic data show that substrate inhibition of the PutA coupled reaction is due to proline binding in the GSAL site. View Full-Text
Keywords: flavoenzyme; proline dehydrogenase; l-glutamate-γ-semialdehyde dehydrogenase; substrate inhibition; X-ray crystallography flavoenzyme; proline dehydrogenase; l-glutamate-γ-semialdehyde dehydrogenase; substrate inhibition; X-ray crystallography
Figures

Graphical abstract

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Korasick, D.A.; Pemberton, T.A.; Arentson, B.W.; Becker, D.F.; Tanner, J.J. Structural Basis for the Substrate Inhibition of Proline Utilization A by Proline. Molecules 2018, 23, 32.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Molecules EISSN 1420-3049 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top