Dataset Information


Small-angle X-ray scattering studies of the oligomeric state and quaternary structure of the trifunctional proline utilization A (PutA) flavoprotein from Escherichia coli.

ABSTRACT: The trifunctional flavoprotein proline utilization A (PutA) links metabolism and gene regulation in Gram-negative bacteria by catalyzing the two-step oxidation of proline to glutamate and repressing transcription of the proline utilization regulon. Small-angle x-ray scattering (SAXS) and domain deletion analysis were used to obtain solution structural information for the 1320-residue PutA from Escherichia coli. Shape reconstructions show that PutA is a symmetric V-shaped dimer having dimensions of 205 × 85 × 55 ?. The particle consists of two large lobes connected by a 30-? diameter cylinder. Domain deletion analysis shows that the N-terminal DNA-binding domain mediates dimerization. Rigid body modeling was performed using the crystal structure of the DNA-binding domain and a hybrid x-ray/homology model of residues 87-1113. The calculations suggest that the DNA-binding domain is located in the connecting cylinder, whereas residues 87-1113, which contain the two catalytic active sites, reside in the large lobes. The SAXS data and amino acid sequence analysis suggest that the ?(1)-pyrroline-5-carboxylate dehydrogenase domains lack the conventional oligomerization flap, which is unprecedented for the aldehyde dehydrogenase superfamily. The data also provide insight into the function of the 200-residue C-terminal domain. It is proposed that this domain serves as a lid that covers the internal substrate channeling cavity, thus preventing escape of the catalytic intermediate into the bulk medium. Finally, the SAXS model is consistent with a cloaking mechanism of gene regulation whereby interaction of PutA with the membrane hides the DNA-binding surface from the put regulon thereby activating transcription.


PROVIDER: S-EPMC3234867 | BioStudies | 2011-01-01

REPOSITORIES: biostudies

Similar Datasets

2016-01-01 | S-EPMC5293562 | BioStudies
2013-01-01 | S-EPMC3731750 | BioStudies
2014-01-01 | S-EPMC4159212 | BioStudies
2010-01-01 | S-EPMC3727237 | BioStudies
2003-01-01 | S-EPMC3727246 | BioStudies
2006-01-01 | S-EPMC1367249 | BioStudies
2017-01-01 | S-EPMC5603418 | BioStudies
2006-01-01 | S-EPMC2242416 | BioStudies
2017-01-01 | S-EPMC6044449 | BioStudies
2008-01-01 | S-EPMC2665032 | BioStudies