Insights into the mode of action of a putative zinc transporter CzrB in Thermus thermophilus.
The crystal structures of the cytoplasmic domain of the putative zinc transporter CzrB in the apo and zinc-bound forms reported herein are consistent with the protein functioning in vivo as a homodimer. NMR, X-ray scattering, and size-exclusion chromatography provide support for dimer formation. Full-length variants of CzrB in the apo and zinc-loaded states were generated by homology modeling with the Zn2+/H+ antiporter YiiP. The model suggests a way in which zinc binding to the cytoplasmic fragment creates a docking site to which a metallochaperone can bind for delivery and transport of its zinc cargo. Because the cytoplasmic domain may exist in the cell as an independent, soluble protein, a proposal is advanced that it functions as a metallochaperone and that it regulates the zinc-transporting activity of the full-length protein. The latter requires that zinc binding becomes uncoupled from the creation of a metallochaperone-docking site on CzrB.
Cherezov
Vadim
V
Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
Höfer
Nicole
N
Szebenyi
Doletha M E
DM
Kolaj
Olga
O
Wall
J Gerard
JG
Gillilan
Richard
R
Srinivasan
Vasundara
V
Jaroniec
Christopher P
CP
Caffrey
Martin
M
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology*; D001665:Binding Sites; D002352:Carrier Proteins / Q000378:metabolism / Q000502:physiology; D018360:Crystallography, X-Ray; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology*; D026901:Membrane Transport Proteins / Q000378:metabolism / Q000502:physiology; D008954:Models, Biological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D016963:Thermus thermophilus / Q000737:chemistry / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism*
D001426:Bacterial Proteins; D002352:Carrier Proteins; C120279:CzrB protein, bacteria; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C017800:zinc-binding protein; D015032:Zinc
Acta Crystallogr D Biol Crystallogr. 1994 Sep 1;50(Pt 5):760-3
15299374
J Am Chem Soc. 2007 Jun 20;129(24):7502-3
17530852
Protein Sci. 1998 Aug;7(8):1700-16
10082367
J Ind Microbiol Biotechnol. 2005 Jun;32(6):215-26
15889311
Biophys J. 1999 Jun;76(6):2879-86
10354416
Methods Enzymol. 1997;276:307-26
27754618
Biopolymers. 1983 Dec;22(12):2577-637
6667333
Anal Biochem. 2000 Dec 15;287(2):252-60
11112271
Acta Crystallogr D Biol Crystallogr. 1997 May 1;53(Pt 3):240-55
15299926
Nucleic Acids Res. 2007 Jul;35(Web Server issue):W375-83
17452350
Acta Crystallogr Sect F Struct Biol Cryst Commun. 2007 Aug 1;63(Pt 8):673-7
17671365
Acta Crystallogr D Biol Crystallogr. 2001 Oct;57(Pt 10):1445-50
11567158
Nucleic Acids Res. 2003 Jul 1;31(13):3381-5
12824332
Acta Crystallogr A. 1991 Mar 1;47 ( Pt 2):110-9
2025413
Nucleic Acids Res. 2007 Jul;35(Web Server issue):W645-8
17526519
Science. 2001 Jun 29;292(5526):2488-92
11397910
Science. 2007 Sep 21;317(5845):1746-8
17717154
BMC Genomics. 2007 Apr 23;8:107
17448255
Acta Crystallogr D Biol Crystallogr. 2004 Dec;60(Pt 12 Pt 1):2126-32
15572765
J Biomol NMR. 1993 Jan;3(1):121-6
8383554
Methods Enzymol. 2003;374:22-37
14696367
Extremophiles. 2002 Aug;6(4):301-8
12215815
Acta Crystallogr D Biol Crystallogr. 1999 Apr;55(Pt 4):849-61
10089316