1xfo
From Proteopedia
Crystal Structure of an archaeal aminopeptidase
Structural highlights
FunctionTET_PYRHO Functions as an aminopeptidase, with a clear preference for leucine as the N-terminal amino acid. However, can also cleave moderately long polypeptide substrates of various compositions in a fairly unspecific manner. Has neither carboxypeptidase nor endoproteolytic activities, and it is devoid of N-terminal deblocking activity. Is involved in protein degradation, performing degradation of oligopeptides produced by the proteasome into single amino acids.[1] [2] [3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedProtein turnover is an essential process in living cells. The degradation of cytosolic polypeptides is mainly carried out by the proteasome, resulting in 7-9-amino acid long peptides. Further degradation is usually carried out by energy-independent proteases like the tricorn protease from Thermoplasma acidophilum. Recently, a novel tetrahedral-shaped dodecameric 480-kDa aminopeptidase complex (TET) has been described in Haloarcula marismortui that differs from the known ring- or barrel-shaped self-compartmentalizing proteases. This complex is capable of degrading most peptides down to amino acids. We present here the crystal structure of the tetrahedral aminopeptidase homolog FrvX from Pyrococcus horikoshii. The monomer has a typical clan MH fold, as found for example in Aeromonas proteolytica aminopeptidase, containing a dinuclear zinc active center. The quaternary structure is built by dimers with a length of 100 A that form the edges of the tetrahedron. All 12 active sites are located on the inside of the tetrahedron. Substrate access is granted by pores with a maximal diameter of 10 A, allowing only small peptides and unfolded proteins access to the active site. Crystal structure of a dodecameric tetrahedral-shaped aminopeptidase.,Russo S, Baumann U J Biol Chem. 2004 Dec 3;279(49):51275-81. Epub 2004 Sep 16. PMID:15375159[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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