TY - JOUR
T1 - Substrate specificity of mammalian N-terminal α-amino methyltransferase NRMT
AU - Petkowski, Janusz J.
AU - Schaner Tooley, Christine E.
AU - Anderson, Lissa C.
AU - Shumilin, Igor A.
AU - Balsbaugh, Jeremy L.
AU - Shabanowitz, Jeffrey
AU - Hunt, Donald F.
AU - Minor, Wladek
AU - MacAra, Ian G.
PY - 2012/7/31
Y1 - 2012/7/31
N2 - N-Terminal methylation of free α-amino groups is a post-translational modification of proteins that was first described 30 years ago but has been studied very little. In this modification, the initiating M residue is cleaved and the exposed α-amino group is mono-, di-, or trimethylated by NRMT, a recently identified N-terminal methyltransferase. Currently, all known eukaryotic α-amino-methylated proteins have a unique N-terminal motif, M-X-P-K, where X is A, P, or S. NRMT can also methylate artificial substrates in vitro in which X is G, F, Y, C, M, K, R, N, Q, or H. Methylation efficiencies of N-terminal amino acids are variable with respect to the identity of X. Here we use in vitro peptide methylation assays and substrate immunoprecipitations to show that the canonical M-X-P-K methylation motif is not the only one recognized by NRMT. We predict that N-terminal methylation is a widespread post-translational modification and that there is interplay between N-terminal acetylation and N-terminal methylation. We also use isothermal calorimetry experiments to demonstrate that NRMT can efficiently recognize and bind to its fully methylated products.
AB - N-Terminal methylation of free α-amino groups is a post-translational modification of proteins that was first described 30 years ago but has been studied very little. In this modification, the initiating M residue is cleaved and the exposed α-amino group is mono-, di-, or trimethylated by NRMT, a recently identified N-terminal methyltransferase. Currently, all known eukaryotic α-amino-methylated proteins have a unique N-terminal motif, M-X-P-K, where X is A, P, or S. NRMT can also methylate artificial substrates in vitro in which X is G, F, Y, C, M, K, R, N, Q, or H. Methylation efficiencies of N-terminal amino acids are variable with respect to the identity of X. Here we use in vitro peptide methylation assays and substrate immunoprecipitations to show that the canonical M-X-P-K methylation motif is not the only one recognized by NRMT. We predict that N-terminal methylation is a widespread post-translational modification and that there is interplay between N-terminal acetylation and N-terminal methylation. We also use isothermal calorimetry experiments to demonstrate that NRMT can efficiently recognize and bind to its fully methylated products.
UR - http://www.scopus.com/inward/record.url?scp=84864431040&partnerID=8YFLogxK
U2 - 10.1021/bi300278f
DO - 10.1021/bi300278f
M3 - Article
C2 - 22769851
AN - SCOPUS:84864431040
SN - 0006-2960
VL - 51
SP - 5942
EP - 5950
JO - Biochemistry
JF - Biochemistry
IS - 30
ER -