2mv3
From Proteopedia
The N-domain of the AAA metalloproteinase Yme1 from Saccharomyces cerevisiae
Structural highlights
FunctionYME1_YEAST Catalytic subunit of the mitochondrial inner membrane i-AAA protease supercomplex required for mitochondrial inner membrane protein turnover. The protease is probably ATP-dependent. Important to maintain the integrity of the mitochondrial compartment. Required both for the degradation of unassembled subunit 2 of cytochrome c oxidase (COX2) and for efficient assembly of mitochondrial respiratory chain. Binds unfolded substrates in an ATPase-independent manner; binding of folded COX2, a physiological substrate, requires an active ATPase but when COX2 is destabilized an active ATPase is no longer necessary.[1] [2] Publication Abstract from PubMedMetalloproteases of the AAA (ATPases associated with various cellular activities) family play a crucial role in protein quality control within the cytoplasmic membrane of bacteria and the inner membrane of eukaryotic organelles. These membrane-anchored hexameric enzymes are composed of an N-terminal domain with one or two transmembrane helices, a central AAA ATPase module, and a C-terminal Zn2+-dependent protease. While the latter two domains have been well studied, so far, little is known about the N-terminal regions. Here, in an extensive bioinformatic and structural analysis, we identified three major, non-homologous groups of N-domains in AAA metalloproteases. By far, the largest one is the FtsH-like group of bacteria and eukaryotic organelles. The other two groups are specific to Yme1: one found in plants, fungi, and basal metazoans and the other one found exclusively in animals. Using NMR and crystallography, we determined the subunit structure and hexameric assembly of Escherichiacoli FtsH-N, exhibiting an unusual alpha+beta fold, and the conserved part of fungal Yme1-N from Saccharomyces cerevisiae, revealing a tetratricopeptide repeat fold. Our bioinformatic analysis showed that, uniquely among these proteins, the N-domain of Yme1 from the cnidarian Hydra vulgaris contains both the tetratricopeptide repeat region seen in basal metazoans and a region of homology to the N-domains of animals. Thus, it is a modern-day representative of an intermediate in the evolution of animal Yme1 from basal eukaryotic precursors. Structure and Evolution of N-domains in AAA Metalloproteases.,Scharfenberg F, Serek-Heuberger J, Coles M, Hartmann MD, Habeck M, Martin J, Lupas AN, Alva V J Mol Biol. 2015 Jan 8. pii: S0022-2836(15)00004-2. doi:, 10.1016/j.jmb.2014.12.024. PMID:25576874[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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