1npp | pdb_00001npp
CRYSTAL STRUCTURE OF AQUIFEX AEOLICUS NUSG IN P2(1)
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| 1npp, resolution 2.00Å | |||||||||||||
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| Ligands: | IPA | ||||||||||||
| Gene: | NUSG OR AQ_1931 (Aquifex aeolicus) | ||||||||||||
| Related: | 1M1G, 1M1H
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||||||
Overview
Transcription factor NusG is present in all prokaryotes, and orthologous proteins have also been identified in yeast and humans. NusG contains a 27-residue KOW motif, found in ribosomal protein L24 where it interacts with rRNA. NusG in Escherichia coli (EcNusG) is an essential protein and functions as a regulator of Rho-dependent transcription termination, phage lambda N and rRNA transcription antitermination, and phage HK022 Nun termination. Relative to EcNusG, Aquifex aeolicus NusG (AaNusG) and several other bacterial NusG proteins contain a variable insertion sequence of approximately 70 residues in the central region of the molecule. Recently, crystal structures of AaNusG in space groups P2(1) and I222 have been reported; the authors conclude that there are no conserved dimers among the contacting molecules in the crystals [Steiner, T., Kaiser, J. T., Marinkovic, S., Huber, R., and Wahl, M. C. (2002) EMBO J. 21, 4641-4653]. We have independently determined the structures of AaNusG also in two crystal forms, P2(1) and C222(1), and surprisingly found that AaNusG molecules form domain-swapped dimers in both crystals. Additionally, polymerization is also observed in the P2(1) crystal. A unique "ball-and-socket" junction dominates the intermolecular interactions within both oligomers. We believe that this interaction is a clue to the function of the molecule and propose a spring-loaded state in the functional cycle of NusG. The importance of the ball-and-socket junction for the function of NusG is supported by the functional analysis of site-directed mutants.
About this Structure
1NPP is a Single protein structure of sequence from Aquifex aeolicus. Full crystallographic information is available from OCA.
Reference
A spring-loaded state of NusG in its functional cycle is suggested by X-ray crystallography and supported by site-directed mutants., Knowlton JR, Bubunenko M, Andrykovitch M, Guo W, Routzahn KM, Waugh DS, Court DL, Ji X, Biochemistry. 2003 Mar 4;42(8):2275-81. PMID:12600194
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