2fzm
From Proteopedia
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| , resolution 2.300Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | and | ||||||
| Gene: | putA (Escherichia coli) | ||||||
| Activity: | Proline dehydrogenase, with EC number 1.5.99.8 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Structure of the E. coli PutA proline dehydrogenase domain reduced by dithionite and complexed with SO2
Overview
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.
About this Structure
2FZM is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Redox-induced changes in flavin structure and roles of flavin N(5) and the ribityl 2'-OH group in regulating PutA--membrane binding., Zhang W, Zhang M, Zhu W, Zhou Y, Wanduragala S, Rewinkel D, Tanner JJ, Becker DF, Biochemistry. 2007 Jan 16;46(2):483-91. PMID:17209558
Page seeded by OCA on Thu Mar 20 16:58:42 2008
