KEGG   ENZYME: 6.2.1.55
Entry
EC 6.2.1.55                 Enzyme                                 

Name
E1 SAMP-activating enzyme;
UbaA;
SAMP-activating enzyme E1
Class
Ligases;
Forming carbon-sulfur bonds;
Acid-thiol ligases
Sysname
[SAMP]:[E1 SAMP-activating enzyme] ligase (AMP-forming)
Reaction(IUBMB)
ATP + [SAMP]-Gly-Gly + [E1 SAMP-activating enzyme]-L-cysteine = S-[[SAMP]-Gly-Gly]-[[E1 SAMP-activating enzyme]-L-cysteine] + AMP + diphosphate (overall reaction);
(1a) ATP + [SAMP]-Gly-Gly = diphosphate + [SAMP]-Gly-Gly-AMP;
(1b) [SAMP]-Gly-Gly-AMP + [E1 SAMP-activating enzyme]-L-cysteine = S-[[SAMP]-Gly-Gly]-[[E1 SAMP-activating enzyme]-L-cysteine] + AMP
Substrate
ATP [CPD:C00002];
[SAMP]-Gly-Gly [CPD:C21900];
[E1 SAMP-activating enzyme]-L-cysteine;
[SAMP]-Gly-Gly-AMP [CPD:C21901]
Product
S-[[SAMP]-Gly-Gly]-[[E1 SAMP-activating enzyme]-L-cysteine];
AMP [CPD:C00020];
diphosphate [CPD:C00013];
[SAMP]-Gly-Gly-AMP [CPD:C21901]
Comment
Contains Zn2+. The enzyme catalyses the activation of SAMPs (Small Archaeal Modifier Proteins), which are ubiquitin-like proteins found only in the Archaea. SAMPs are involved in protein degradation, and also act as sulfur carriers involved in thiolation of tRNA and other metabolites such as molybdopterin. The enzyme catalyses the ATP-dependent formation of a SAMP adenylate intermediate in which the C-terminal glycine of SAMP is bound to AMP via an acyl-phosphate linkage (reaction 1). This intermediate can accept a sulfur atom to form a thiocarboxylate moiety in a mechanism that is not yet understood. Alternatively, the E1 enzyme can transfer SAMP from its activated form to an internal cysteine residue, releasing AMP (reaction 2). In this case SAMP is subsequently transferred to a lysine residue in a target protein in a process termed SAMPylation. Auto-SAMPylation (attachment of SAMP to lysine residues within the E1 enzyme) has been observed. cf. EC 2.7.7.100, SAMP-activating enzyme.
History
EC 6.2.1.55 created 2018
Reference
1  [PMID:21368171]
  Authors
Miranda HV, Nembhard N, Su D, Hepowit N, Krause DJ, Pritz JR, Phillips C, Soll D, Maupin-Furlow JA
  Title
E1- and ubiquitin-like proteins provide a direct link between protein conjugation and sulfur transfer in archaea.
  Journal
Proc Natl Acad Sci U S A 108:4417-22 (2011)
DOI:10.1073/pnas.1018151108
  Sequence
[hvo:HVO_0558]
Reference
2  [PMID:23140889]
  Authors
Maupin-Furlow JA
  Title
Ubiquitin-like proteins and their roles in archaea.
  Journal
Trends Microbiol 21:31-8 (2013)
DOI:10.1016/j.tim.2012.09.006
Reference
3  [PMID:24097257]
  Authors
Miranda HV, Antelmann H, Hepowit N, Chavarria NE, Krause DJ, Pritz JR, Basell K, Becher D, Humbard MA, Brocchieri L, Maupin-Furlow JA
  Title
Archaeal ubiquitin-like SAMP3 is isopeptide-linked to proteins via a UbaA-dependent mechanism.
  Journal
Mol Cell Proteomics 13:220-39 (2014)
DOI:10.1074/mcp.M113.029652
  Sequence
[hvo:HVO_0558]
Reference
4  [PMID:27459543]
  Authors
Hepowit NL, de Vera IM, Cao S, Fu X, Wu Y, Uthandi S, Chavarria NE, Englert M, Su D, Sll D, Kojetin DJ, Maupin-Furlow JA
  Title
Mechanistic insight into protein modification and sulfur mobilization activities  of noncanonical E1 and associated ubiquitin-like proteins of Archaea.
  Journal
FEBS J 283:3567-3586 (2016)
DOI:10.1111/febs.13819
  Sequence
[hvo:HVO_0558]
Other DBs
ExplorEnz - The Enzyme Database: 6.2.1.55
IUBMB Enzyme Nomenclature: 6.2.1.55
ExPASy - ENZYME nomenclature database: 6.2.1.55
BRENDA, the Enzyme Database: 6.2.1.55

  All links  
No link information was found.   
DBGET integrated database retrieval system