Transferases;
Transferring one-carbon groups;
Methyltransferases
BRITE hierarchy

S-adenosyl-L-methionine:2-[(3S)-3-carboxy-3-aminopropyl]-L-histidine-[translation elongation factor 2] methyltransferase (diphthine-[translation elongation factor 2]-forming)

3 S-adenosyl-L-methionine + 2-[(3S)-3-carboxy-3-aminopropyl]-L-histidine-[translation elongation factor 2] = 3 S-adenosyl-L-homocysteine + diphthine-[translation elongation factor 2] (overall reaction) [RN:R10306];
(1a) S-adenosyl-L-methionine + 2-[(3S)-3-carboxy-3-aminopropyl]-L-histidine-[translation elongation factor 2] = S-adenosyl-L-homocysteine + 2-[(3S)-3-carboxy-3-(methylamino)propyl]-L-histidine-[translation elongation factor 2] [RN:R04481];
(1b) S-adenosyl-L-methionine + 2-[(3S)-3-carboxy-3-(methylamino)propyl]-L-histidine-[translation elongation factor 2] = S-adenosyl-L-homocysteine + 2-[(3S)-3-carboxy-3-(dimethylamino)propyl]-L-histidine-[translation elongation factor 2] [RN:R08468];
(1c) S-adenosyl-L-methionine + 2-[(3S)-3-carboxy-3-(dimethylamino)propyl]-L-histidine-[translation elongation factor 2] = S-adenosyl-L-homocysteine + diphthine-[translation elongation factor 2] [RN:R08469]

R04481 R08468 R08469 R10306
Reaction

S-adenosyl-L-methionine [CPD:C00019];
2-[(3S)-3-carboxy-3-aminopropyl]-L-histidine-[translation elongation factor 2] [CPD:C04441];
2-[(3S)-3-carboxy-3-(methylamino)propyl]-L-histidine-[translation elongation factor 2] [CPD:C04692];
2-[(3S)-3-carboxy-3-(dimethylamino)propyl]-L-histidine-[translation elongation factor 2] [CPD:C16720]

This archaeal enzyme produces the trimethylated product diphthine, which is converted into diphthamide by EC 6.3.1.14, diphthine---ammonia ligase. Different from the eukaryotic enzyme, which produces diphthine methyl ester (cf. EC 2.1.1.314). In the archaeon Pyrococcus horikoshii the enzyme acts on His600 of elongation factor 2.

EC 2.1.1.98 created 1990, modified 2013, modified 2015

1  [PMID:20873788]