3uo3
From Proteopedia
Jac1 co-chaperone from Saccharomyces cerevisiae, 5-182 clone
Structural highlights
Function[JAC1_YEAST] Co-chaperone required for the assembly of iron-sulfur (Fe/S) clusters in mitochondria. Stimulates the ATPase activity of its specialized Hsp70 chaperone partner SSQ1. Binds to the substrate protein ISU1 and targets it to SSQ1. May function together with SSQ1 in the dislocation of the Fe/S cluster from ISU1 and its insertion into apoproteins.[1] [2] [3] [4] [5] [6] [7] [8] [9] Publication Abstract from PubMedThe ubiquitous mitochondrial J-protein Jac1, called HscB in Escherichia coli, and its partner Hsp70 play a critical role in the transfer of Fe-S clusters from the scaffold protein Isu to recipient proteins. Biochemical results from eukaryotic and prokaryotic systems indicate that formation of the Jac1-Isu complex is important for both targeting of the Isu for Hsp70 binding and stimulation of Hsp70's ATPase activity. However, in apparent contradiction, we previously reported that an 8-fold decrease in Jac1's affinity for Isu1 is well tolerated in vivo, raising the question as to whether the Jac1:Isu interaction actually plays an important biological role. Here, we report the determination of the structure of Jac1 from Saccharomyces cerevisiae. Taking advantage of this information and recently published data from the homologous bacterial system, we determined that a total of eight surface-exposed residues play a role in Isu binding, as assessed by a set of biochemical assays. A variant having alanines substituted for these eight residues was unable to support growth of a jac1-Delta strain. However, replacement of three residues caused partial loss of function, resulting in a significant decrease in the Jac1:Isu1 interaction, a slow growth phenotype, and a reduction in the activity of Fe-S cluster-containing enzymes. Thus, we conclude that the Jac1:Isu1 interaction plays an indispensable role in the essential process of mitochondrial Fe-S cluster biogenesis. Interaction of j-protein co-chaperone jac1 with fe-s scaffold isu is indispensable in vivo and conserved in evolution.,Ciesielski SJ, Schilke BA, Osipiuk J, Bigelow L, Mulligan R, Majewska J, Joachimiak A, Marszalek J, Craig EA, Dutkiewicz R J Mol Biol. 2012 Mar 16;417(1-2):1-12. Epub 2012 Jan 27. PMID:22306468[10] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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Categories: Baker's yeast | Large Structures | Babnigg, G | Bigelow, L | Craig, E A | Dutkiewicz, R | Feldmann, B | Joachimiak, A | Structural genomic | Marszalek, J | Mulligan, R | Osipiuk, J | Chaperone | Co-chaperone | Iron sulfur cluster biogenesis | Isu protein | J-protein | Mcsg | Psi-biology | Ssq1 hsp70 chaperone
