| Structural highlights
4eyy is a 2 chain structure with sequence from Legpc and Legph. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
| | Related: | 3fxd, 3fxe |
| Gene: | icmR, lpg0443 (LEGPH), icmQ, LPC_2899 (LEGPC) |
| Resources: | FirstGlance, OCA, RCSB, PDBsum |
Publication Abstract from PubMed
A Type 4b secretion system (T4bSS) is required for Legionella growth in alveolar macrophages. IcmQ associates with IcmR, binds to membranes, and has a critical role in the T4bSS. We have now solved a crystal structure of IcmR-IcmQ to further our understanding of this complex. This structure revealed an amphipathic four-helix bundle, formed by IcmR and the N-terminal domain of IcmQ, which is linked to a novel C-terminal domain of IcmQ (Qc) by a linker helix. The Qc domain has structural homology with ADP ribosyltransferase domains in certain bacterial toxins and binds NAD(+) with a dissociation constant in the physiological range. Structural homology and molecular dynamics were used to identify an extended NAD(+) binding site on Qc, and the resulting model was tested by mutagenesis and binding assays. Based on the data, we suggest that IcmR-IcmQ binds to membranes, where it may interact with, or perhaps modify, a protein in the T4bSS when NAD(+) is bound.
IcmQ in the Type 4b secretion system contains an NAD+ binding domain.,Farelli JD, Gumbart JC, Akey IV, Hempstead A, Amyot W, Head JF, McKnight CJ, Isberg RR, Akey CW Structure. 2013 Aug 6;21(8):1361-73. doi: 10.1016/j.str.2013.05.017. Epub 2013, Jul 11. PMID:23850453[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Farelli JD, Gumbart JC, Akey IV, Hempstead A, Amyot W, Head JF, McKnight CJ, Isberg RR, Akey CW. IcmQ in the Type 4b secretion system contains an NAD+ binding domain. Structure. 2013 Aug 6;21(8):1361-73. doi: 10.1016/j.str.2013.05.017. Epub 2013, Jul 11. PMID:23850453 doi:http://dx.doi.org/10.1016/j.str.2013.05.017
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