coli at a very low external substrate concentration, the Tsx channel is likely to contain a binding site for this antibiotic. To identify residues involved in the Tsx substrate-specific channel activity, we devised a selection scheme to isolate albicidin-resistant tsx mutants synthesizing Tsx ...
These proteins are thought to function as a scaffold (ExbB)16,17 and to harness the proton motive force (ExbD)18, a pre-requisite for TonB-dependent activity. While it is known that TonB-mediated transport requires TonB to be tethered to an energized IM19, the mechanism by which TonB ...
As a consequence, it accumulated FeMo-co-deficient apo-NifDK and was impaired in NifDK activity. We conclude that FdxN plays a role in FeMo-co biosynthesis, presumably by donating electrons to support NifB-co synthesis by NifB. This is the first role in nitrogenase biosynthesis unequivocally...
High-molecular-weight (Ub)n-GFPu∗ conjugates were rescued by re-expressing wild-type UBE3C, but not UBE3CC1051A, in UBE3CKO cells, confirming that catalytic activity of this E3 is essential for chain extension on oligoubiquitylated GFPu∗ (Figure 2G). In addition to catalyzing K48-...
For example, highly regulatable promoters often have very low basal activity and are dependent on many accessory transcription factors, while extremely strong promoters are less modulatable. A similar concept may apply to translocation, in which signal sequences whose interactions with the translocon ...
18.67±2.579 s–1 1.2 USP5+Ub1–71 Km = 247.8±61.72 μM 0.9 kcat = 51.77±9.298 s–1 0.6 0.6 0.3 0.3 00 0 50 100 150 0 50 100 150 Substrate (μM) Substrate (μM) Figure 4 | The critical role of the b-grasp domain of SUMO1 on binding and activity enhancement of SENP1. ...
Alteration of residues located at the cytoplasmic or the inner membrane interface resulted in lower activity in vivo and in vitro, while variants affecting residues in the central region of the channel showed increased DNA and protein transfer efficiency and higher ATPase activity, especially in the ...
These findings likely represent general properties of the mechanism of substrate recognition and processing by SENPs and other Ubl-specific proteases, and illuminate how adaptive substrate binding can allosterically enhance enzyme activity.doi:10.1038/ncomms5968Chen, Chih-Hong...