2FZM

Structure of the E. coli PutA proline dehydrogenase domain reduced by dithionite and complexed with SO2

Summary for 2FZM

• Entry DOI: 10.2210/pdb2fzm/pdb
• Descriptor: Bifunctional protein putA, Proline dehydrogenase (EC 1.5.99.8) (Proline oxidase), FLAVIN-ADENINE DINUCLEOTIDE, SULFUR DIOXIDE, ... (4 entities in total)
• Functional Keywords: proline utilization a, proline dehydrogenase, puta, flavoenzyme, proline catabolism, dithionite-reduced, oxidoreductase
• Biological source: Escherichia coli
• Total number of polymer chains: 1
• Total formula weight: 67517.68

Authors

Tanner, J.J. (deposition date: 2006-02-09, release date: 2007-04-03, Last modification date: 2023-08-30)

Primary citation

Zhang, W.,Zhang, M.,Zhu, W.,Zhou, Y.,Wanduragala, S.,Rewinkel, D.,Tanner, J.J.,Becker, D.F.
Redox-induced changes in flavin structure and roles of flavin N(5) and the ribityl 2'-OH group in regulating PutA--membrane binding.
Biochemistry, 46:483-491, 2007

PubMed Abstract: PutA is a novel flavoprotein in Escherichia coli that switches from a transcriptional repressor to a membrane-bound proline catabolic enzyme. Previous crystallographic studies of the PutA proline dehydrogenase (PRODH) domain under oxidizing conditions revealed that FAD N(5) and the ribityl 2'-OH group form hydrogen bonds with Arg431 and Arg556, respectively. Here we identify molecular interactions in the PutA PRODH active site that underlie redox-dependent functional switching of PutA. We report that reduction of the PRODH domain induces major structural changes in the FAD cofactor, including a 22 degrees bend of the isoalloxazine ring along the N(5)-N(10) axis, crankshaft rotation of the upper part of the ribityl chain, and formation of a new hydrogen bond network involving the ribityl 2'-OH group, FAD N(1), and Gly435. The roles of the FAD 2'-OH group and the FAD N(5)-Arg431 hydrogen bond pair in regulating redox-dependent PutA-membrane associations were tested using FAD analogues and site-directed mutagenesis. Kinetic membrane binding measurements and cell-based reporter gene assays of modified PutA proteins show that disrupting the FAD N(5)-Arg431 interaction impairs the reductive activation of PutA-membrane binding. We also show that the FAD 2'-OH group acts as a redox-sensitive toggle switch that controls PutA-membrane binding. These results illustrate a new versatility of the ribityl chain in flavoprotein mechanisms.

PubMed: 17209558
DOI: 10.1021/bi061935g

Experimental method

X-RAY DIFFRACTION (2.3 Å)