Structural and transcriptional analyses of a purine nucleotide-binding protein from Pyrococcus furiosus: a component of a novel, membrane-bound multiprotein complex unique to this hyperthermophilic archaeon.
The open-reading frame PF0895 in the genome of the hyperthermophilic archaeon, Pyrococcus furiosus, encodes a 206-residue protein (M(R )23,152). The structure of the recombinant protein was solved by single isomorphous replacement with anomalous scattering (SIRAS) using a mercury derivative. It has been refined to 1.70 A with a crystallographic R and R(free )values of 19.7% and 22.3%, respectively. The PF0895 structure is similar to those of the ATP binding cassettes observed in the ABC transporter family. However, bioinformatics and molecular analyses indicate that PF0895 is not part of the expected five-gene operon that encodes a typical prokaryotic solute-binding ABC transporter. Rather, transcriptional profiling data show that PF0895 is part of a novel four-gene operon (PF0895-PF0896-PF0897-PF0897.1) where only PF0895 has homologs in other organisms. Interestingly, from genome analysis, P. furiosus itself contains a second version of this complex, encoded by PF1090-PF1093. From the structural studies we can only conclude that one of the subunits of this novel membrane complex, PF0895, and its homolog PF1090, likely bind a purine nucleotide. PF0895 is therefore predicted to be part of a membrane-bound multiprotein complex unrelated to ABC transporters that is so far unique to P. furiosus. It appears to play a role in the stress response, as its expression is down regulated when the organism is subjected to cold-shock, where cells are transferred from 95 degrees C, near the optimal growth temperature, to 72 degrees C, near the minimal growth temperature. The related PF1090-containing operon is unaffected by cold-shock and is independently regulated.
Gerwe
Brian
B
Southeast Collaboratory for Structural Genomics, Department of Biochemistry and Molecular Biology, University of Georgia, Davison Life Science Complex, Athens, GA 30602, USA.
Kelley
Laura-Lee Clancy
LL
Dillard
Bret D
BD
Lai
Thomas
T
Liu
Zhi-Jie
ZJ
Tempel
Wolfram
W
Chen
Lirong
L
Habel
Jeff
J
Lee
Doowon
D
Jenney
Francis E
FE
Sugar
Frank J
FJ
Richardson
Jane S
JS
Richardson
David C
DC
Newton
M Gary
MG
Wang
Bi-Cheng
BC
Adams
Michael W W
MW
Rose
John P
JP
D000595:Amino Acid Sequence; D001692:Biological Transport; D018360:Crystallography, X-Ray; D019848:Gene Expression Regulation, Archaeal; D020745:Genome, Archaeal; D023281:Genomics; D008954:Models, Biological; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000737:chemistry*; D033704:Nucleotide Transport Proteins / Q000737:chemistry* / Q000502:physiology; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D020027:Pyrococcus furiosus / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
D046912:Multiprotein Complexes; D033704:Nucleotide Transport Proteins; D011506:Proteins