The mode of membrane attachment of the Rieske iron-sulfur protein from cytochrome bc1 complex of Rhodospirillum rubrum has been studied using biochemical approaches. In contrast to cytochrome c1 the bacterial Rieske protein was extracted from chromatophores using chaotropic agents (NaSCN, urea, guanidine), an alkaline pH and relatively low concentration of Triton X-100. The results presented he...

Nitrogenase activity in Rhodospirillum rubrum is post-translationally regulated by DRAG (dinitrogenase reductase glycohydrolase) and DRAT (dinitrogenase reductase ADP-ribosylation transferase). When a sudden increase in fixed nitrogen concentration or energy depletion is sensed by the cells, DRAG is inactivated and DRAT activated. We propose that the regulation of DRAG is dependent on its locat...

We have measured the photoresponse of two purple nonsulfur bacteria, Rhodobacter sphaeroides and Rhodospirillum centenum, under defined conditions in a light beam propagating at 90 degrees to the optical axis of the microscope. This beam presented cells with a steep gradient of intensity perpendicular to the direction of propagation and a shallow gradient in the direction of light propagation. ...

The oxidation of acetic acid in the dark by the non-sulfur purple bacterium, Rhodospirillum rubrum, was shown by van Niel (1, 2) to require the presence of either carbon dioxide or trace amounts of the Cb-dicarboxylic acids of the Krebs cycle. These results could readily be interpreted to mean that the oxidation of acetic acid proceeds by way of the Krebs cycle, the presence of COZ being requir...

Chemical modification of spinach ribulosebisphosphate carboxylase/oxygenase by diethyl pyrocarbonate led to the conclusion that His-298 is an essential activesite residue (Igarashi, Y., McFadden, B. A., and ElGul, T. (1985) Biochemistry 24, 3957-3962). From the pH dependence of inactivation, the pKa of His-298 was observed to be -6.8, and it was uggested that this histidine might be the essenti...