6od1
From Proteopedia
IraD-bound to RssB D58P variant
Structural highlights
Function[V0SNG0_ECOLX] Regulates the turnover of the sigma S factor (RpoS) by promoting its proteolysis in exponentially growing cells. Acts by binding and delivering RpoS to the ClpXP protease. RssB is not co-degraded with RpoS, but is released from the complex and can initiate a new cycle of RpoS recognition and degradation.[HAMAP-Rule:MF_00958] [IRAD_ECOLI] Inhibits RpoS proteolysis by regulating RssB activity, thereby increasing the stability of the sigma stress factor RpoS during oxidative stress. Its effect on RpoS stability is due to its interaction with RssB, which probably blocks the interaction of RssB with RpoS, and the consequent delivery of the RssB-RpoS complex to the ClpXP protein degradation pathway.[1] Publication Abstract from PubMedThe stationary phase promoter specificity subunit sigma(S) (RpoS) is delivered to the ClpXP machinery for degradation dependent on the adaptor RssB. This adaptor-specific degradation of sigma(S) provides a major point for regulation and transcriptional reprogramming during the general stress response. RssB is an atypical response regulator and the only known ClpXP adaptor that is inhibited by multiple but dissimilar antiadaptors (IraD, IraP, and IraM). These are induced by distinct stress signals and bind to RssB in poorly understood manners to achieve stress-specific inhibition of sigma(S) turnover. Here we present the first crystal structure of RssB bound to an antiadaptor, the DNA damage-inducible IraD. The structure reveals that RssB adopts a compact closed architecture with extensive interactions between its N-terminal and C-terminal domains. The structural data, together with mechanistic studies, suggest that RssB plasticity, conferred by an interdomain glutamate-rich flexible linker, is critical for regulation of sigma(S) degradation. Structural modulation of interdomain linkers may thus constitute a general strategy for tuning response regulators. Structural basis for inhibition of a response regulator of sigma(S) stability by a ClpXP antiadaptor.,Dorich V, Brugger C, Tripathi A, Hoskins JR, Tong S, Suhanovsky MM, Sastry A, Wickner S, Gottesman S, Deaconescu AM Genes Dev. 2019 Apr 11. pii: gad.320168.118. doi: 10.1101/gad.320168.118. PMID:30975721[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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