1NPP

CRYSTAL STRUCTURE OF AQUIFEX AEOLICUS NUSG IN P2(1)

Summary for 1NPP

• Entry DOI: 10.2210/pdb1npp/pdb
• Related: 1M1G 1M1H 1NPR
• Descriptor: Transcription antitermination protein nusG, ISOPROPYL ALCOHOL (3 entities in total)
• Functional Keywords: rnap transcription factor, nusg, transcription
• Biological source: Aquifex aeolicus
• Total number of polymer chains: 4
• Total formula weight: 112287.00

Authors

Knowlton, J.R.,Bubunenko, M.,Andrykovitch, M.,Guo, W.,Routzahn, K.M.,Waugh, D.S.,Court, D.L.,Ji, X. (deposition date: 2003-01-18, release date: 2003-03-11, Last modification date: 2024-10-30)

Primary citation

Knowlton, J.R.,Bubunenko, M.,Andrykovitch, M.,Guo, W.,Routzahn, K.M.,Waugh, D.S.,Court, D.L.,Ji, X.
A Spring-Loaded State of NusG in Its Functional Cycle Is Suggested by X-ray Crystallography and Supported by Site-Directed Mutants
Biochemistry, 42:2275-2281, 2003

PubMed Abstract: 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.

PubMed: 12600194
DOI: 10.1021/bi0272508

Experimental method

X-RAY DIFFRACTION (2 Å)