2QH1

Structure of TA289, a CBS-rubredoxin-like protein, in its Fe+2-bound state

Summary for 2QH1

• Entry DOI: 10.2210/pdb2qh1/pdb
• Related: 1PVM
• Descriptor: Hypothetical protein Ta0289, FE (II) ION (3 entities in total)
• Functional Keywords: cbs-rubredoxin-like protein, fe+2, hypothetical protein, unknown function, structural genomics, structural genomics consortium, sgc, psi-2, protein structure initiative, midwest center for structural genomics, mcsg
• Biological source: Thermoplasma acidophilum
• Total number of polymer chains: 2
• Total formula weight: 45043.37

Authors

Singer, A.U.,Proudfoot, M.,Brown, G.,Xu, L.,Savchenko, A.,Yakunin, A.F.,Midwest Center for Structural Genomics (MCSG) (deposition date: 2007-06-29, release date: 2008-02-19, Last modification date: 2023-08-30)

Primary citation

Proudfoot, M.,Sanders, S.A.,Singer, A.,Zhang, R.,Brown, G.,Binkowski, A.,Xu, L.,Lukin, J.A.,Murzin, A.G.,Joachimiak, A.,Arrowsmith, C.H.,Edwards, A.M.,Savchenko, A.V.,Yakunin, A.F.
Biochemical and structural characterization of a novel family of cystathionine beta-synthase domain proteins fused to a Zn ribbon-like domain.
J.Mol.Biol., 375:301-315, 2008

PubMed Abstract: We have identified a novel family of proteins, in which the N-terminal cystathionine beta-synthase (CBS) domain is fused to the C-terminal Zn ribbon domain. Four proteins were overexpressed in Escherichia coli and purified: TA0289 from Thermoplasma acidophilum, TV1335 from Thermoplasma volcanium, PF1953 from Pyrococcus furiosus, and PH0267 from Pyrococcus horikoshii. The purified proteins had a red/purple color in solution and an absorption spectrum typical of rubredoxins (Rds). Metal analysis of purified proteins revealed the presence of several metals, with iron and zinc being the most abundant metals (2-67% of iron and 12-74% of zinc). Crystal structures of both mercury- and iron-bound TA0289 (1.5-2.0 A resolution) revealed a dimeric protein whose intersubunit contacts are formed exclusively by the alpha-helices of two cystathionine beta-synthase subdomains, whereas the C-terminal domain has a classical Zn ribbon planar architecture. All proteins were reversibly reduced by chemical reductants (ascorbate or dithionite) or by the general Rd reductase NorW from E. coli in the presence of NADH. Reduced TA0289 was found to be capable of transferring electrons to cytochrome C from horse heart. Likewise, the purified Zn ribbon protein KTI11 from Saccharomyces cerevisiae had a purple color in solution and an Rd-like absorption spectrum, contained both iron and zinc, and was reduced by the Rd reductase NorW from E. coli. Thus, recombinant Zn ribbon domains from archaea and yeast demonstrate an Rd-like electron carrier activity in vitro. We suggest that, in vivo, some Zn ribbon domains might also bind iron and therefore possess an electron carrier activity, adding another physiological role to this large family of important proteins.

PubMed: 18021800
DOI: 10.1016/j.jmb.2007.10.060

Experimental method

X-RAY DIFFRACTION (2 Å)