NatA acetyltransferase
NatA acetyltransferase(N
Forty percent of all proteins in the yeast proteome are thought to be N-terminally acetylated, with a corresponding figure of 90% in mammalian proteins.[1]
To be specific, NatA is the main N{alpha}-terminal acetyltransferase in the yeast cytosol, responsible for the acetylation of proteins at locations in which L-serine, L-alanine, L-threonine, or glycine are present.[2][3]
NatA Acetyltransferase is not a single protein but a complex of three subunits.
Sup35p acetylation[edit]
In Saccharomyces cerevisiae NatA acetyltransferase interacts with the Sup35p protein. It is involved in the reaction of the [PSI+], converting the [psi-] to its own conformation. Thus, [PSI+] strains deficient in NatA Acetyltransferase have been found to have an altered interaction between Sup35p[PSI+] and nascent Sup35p. This interaction at the post-translational level still produces a prion with classical beta sheets, but this version of the interaction does not take away the function of this third release factor. Thus, stop codons are translated reliably in [PSI+] strains lacking NatA Acetyltransferase.[4]
Subunits in yeast[edit]
- Naa10 (formerly Nat1p) – 27kDA, has catalytic properties which acetylate the nascent polypeptide.
- Naa15 (formerly Ard1p) – 98kDa, functions to bind to anchor onto the ribosome.
- Naa50 (formerly Nat5p) – Newly discovered, unknown function.
Yeast cells lacking Naa15 and Naa10 show a reduced sporulation efficiency, failure to enter G0 phase under specific conditions, defect in silencing of the silent mating-type loci, and decreased survival after heat shock. However, strains lacking Naa50 do not show any obvious difference to the phenotype.
Comparisons[edit]
Natp requires longer nascent polypeptide chains to function catalystically than NAC (nascent polypeptide-associated complex) and Hsp70 homologue Ssb1/2p.
References[edit]
- ^ Caesar, Robert, Jonas Warringer, and Anders Blomberg. "Physiological Importance and Identification of Novel Targets for the N-Terminal Acetyltransferase NatB – Caesar et al. 5 (2): 368 --." Eukaryotic Cell. 16 December 2005. Web. 31 January 2010. <http://ec.asm.org/cgi/content/full/5/2/368>.
- ^ Gautschi, Matthias, Sören Just, Andrej Mun, Suzanne Ross, Peter Rücknagel, Yves Dubaquié, Ann Ehrenhofer-Murray, and Sabine Rospert. "The Yeast N{alpha}-Acetyltransferase NatA Is Quantitatively Anchored to the Ribosome and Interacts with Nascent Polypeptides." (2003). Molecular and Cellular Biology. Web. 22 January 2010. <http://mcb.asm.org/cgi/content/full/23/20/7403>.
- ^ Polevoda, Bogdan, Jason Hoskins, and Fred Sherman. "Properties of Nat4, an N{alpha}-Acetyltransferase of Saccharomyces cerevisiae That Modifies N Termini of Histones H2A and H4 – Polevoda et al. 29 (11): 2913 --." Molecular and Cellular Biology. Web. 25 January 2010. <http://mcb.asm.org/cgi/content/full/29/11/2913>.
- ^ "The NatA Acetyltransferase Couples Sup35 Prion Complexes to the [PSI ] Phenotype – Pezza et al. 20 (3): 1068– ." Molecular Biology of the Cell. (2008) <http://www.molbiolcell.org/cgi/content/full/20/3/1068>.