Molecular mechanisms for multitasking: recent crystal structures of moonlighting proteins.
Recently determined X-ray crystal structures of moonlighting proteins are helping to elucidate how a protein can evolve two different functions and, in some cases, switch between its two functions in response to cellular conditions. X-ray crystal structures of the I-AniI homing endonuclease/maturase and the PutA proline dehydrogenase/transcription factor have provided evidence that these proteins utilize separate protein surfaces for their multiple functions. Also, the structure of the DegP (HtrA) protease/chaperone has revealed information about the mechanism of its chaperone activity and suggests how the protein regulates its protease activity. Comparing the structure of eta-crystallin/retinal dehydrogenase with structures of its single-function enzyme homologs provides clues to changes in the protein structure that may have improved its ability to serve as a crystallin, but at the same time may have adversely affected its catalytic activity.
Jeffery
Constance J
CJ
Laboratory for Molecular Biology, Department of Biological Sciences, MC567, University of Illinois at Chicago, 900 South Ashland Avenue, Chicago, Illinois 60607, USA.
D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D002384:Catalysis; D003459:Crystallins / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray / Q000379:methods*; D004789:Enzyme Activation; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000378:metabolism; D007527:Isoenzymes / Q000737:chemistry / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D008954:Models, Biological; D008958:Models, Molecular; D008967:Molecular Biology / Q000379:methods; D033903:Periplasmic Proteins / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D012194:RNA-Directed DNA Polymerase / Q000737:chemistry* / Q000378:metabolism; D012697:Serine Endopeptidases / Q000737:chemistry* / Q000378:metabolism; D013329:Structure-Activity Relationship
D001426:Bacterial Proteins; D003459:Crystallins; D006360:Heat-Shock Proteins; D007527:Isoenzymes; D008565:Membrane Proteins; D033903:Periplasmic Proteins; C080683:PutA protein, Bacteria; D012194:RNA-Directed DNA Polymerase; C454879:maturase I-AniI; C061682:DegP protease; D012697:Serine Endopeptidases