|Gene:||hinT||Accession Numbers: EG12172 (MetaCyc), b1103, ECK1089|
Species: Escherichia coli K-12 substr. MG1655
HinT is a purine nucleoside phosphoramidase with a preference for purine nucleoside phosphoramidates. The enzyme is a homolog of the histidine triad nucleotide-binding proteins (Hint) [Chou05]. The presence of a phosphoramidase activity in E. coli was first shown by [Smith59].
In search of the physiological substrate for HinT, it was found that HinT can be adenylated by lysyl-tRNA synthetase (LysRS) in the presence of Mg2+ and lysine; the reaction is inhibited by Zn2+, Ap4A and Ap3A and enhanced by the presence of pyrophosphatase. These experiments suggest that the lysyl-AMP intermediate that is formed by LysRS is the natural substrate for HinT [Chou07].
The substrate specificity of the enzyme has been investigated; in contrast with the human enzyme, no stereochemical preference or preference for substitution at the α carboxylate was found for the E. coli enzyme [Chou07a]. The divergent C-terminal loop region of the enzyme appears to be responsible for substrate specificity [Chou07b].
hinT is essential for growth under high salt conditions [Chou05].
HinT: "histidine triad nucleotide-binding motif"
|Map Position: [1,161,108 -> 1,161,467]|
Molecular Weight of Polypeptide: 13.241 kD (from nucleotide sequence)
Molecular Weight of Multimer: 27.4 kD (experimental) [Chou05]
Unification Links: ASAP:ABE-0003729 , DIP:DIP-48009N , EchoBASE:EB2090 , EcoGene:EG12172 , EcoliWiki:b1103 , Mint:MINT-1266101 , ModBase:P0ACE7 , OU-Microarray:b1103 , PortEco:hinT , PR:PRO_000022888 , Pride:P0ACE7 , Protein Model Portal:P0ACE7 , RefSeq:NP_415621 , RegulonDB:EG12172 , SMR:P0ACE7 , String:511145.b1103 , Swiss-Model:P0ACE7 , UniProt:P0ACE7
Relationship Links: InterPro:IN-FAMILY:IPR001310 , InterPro:IN-FAMILY:IPR011146 , InterPro:IN-FAMILY:IPR019808 , Panther:IN-FAMILY:PTHR23089 , PDB:Structure:3N1S , PDB:Structure:3N1T , Pfam:IN-FAMILY:PF01230 , Prints:IN-FAMILY:PR00332 , Prosite:IN-FAMILY:PS00892 , Prosite:IN-FAMILY:PS51084
|Biological Process:||GO:0055130 - D-alanine catabolic process [Bardaweel11]|
|Molecular Function:||GO:0043530 - adenosine 5'-monophosphoramidase activity
GO:0000166 - nucleotide binding [UniProtGOA11]
GO:0003824 - catalytic activity [GOA01]
GO:0016787 - hydrolase activity [UniProtGOA11]
|Cellular Component:||GO:0005829 - cytosol [DiazMejia09, Ishihama08]|
Enzymatic reaction of: purine nucleoside phosphoramidase
EC Number: 3.9.1.-
The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction of enzyme catalysis.
The reaction is physiologically favored in the direction shown.
Kinetic parameters for a number of substrates have been measured [Chou07a].
|Feature Class||Location||Attached Group||Citations||Comment|
|Conserved-Region||6 -> 115|
|Nucleotide-Phosphate-Binding-Region||30 -> 32||Purine nucleotide phosphoramidate|
|Nucleotide-Phosphate-Binding-Region||96 -> 97||Purine nucleotide phosphoramidate|
|Protein-Segment||99 -> 103|
|Nucleotide-Phosphate-Binding-Region||101 -> 103||Purine nucleotide phosphoramidate|
|Mutagenesis-Variant||114 -> 119|
|Mutagenesis-Variant||117 -> 119|
10/20/97 Gene b1103 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG12172.
Bardaweel11: Bardaweel S, Ghosh B, Chou TF, Sadowsky MJ, Wagner CR (2011). "E. coli histidine triad nucleotide binding protein 1 (ecHinT) is a catalytic regulator of D-alanine dehydrogenase (DadA) activity in vivo." PLoS One 6(7);e20897. PMID: 21754980
Chou05: Chou TF, Bieganowski P, Shilinski K, Cheng J, Brenner C, Wagner CR (2005). "31P NMR and genetic analysis establish hinT as the only Escherchia coli purine nucleoside phosphoramidase and as essential for growth under high salt conditions." J Biol Chem 280(15);15356-61. PMID: 15703176
Chou07a: Chou TF, Baraniak J, Kaczmarek R, Zhou X, Cheng J, Ghosh B, Wagner CR (2007). "Phosphoramidate pronucleotides: a comparison of the phosphoramidase substrate specificity of human and Escherichia coli histidine triad nucleotide binding proteins." Mol Pharm 4(2);208-17. PMID: 17217311
Chou07b: Chou TF, Sham YY, Wagner CR (2007). "Impact of the C-terminal loop of histidine triad nucleotide binding protein1 (Hint1) on substrate specificity." Biochemistry 46(45);13074-9. PMID: 17939685
DiazMejia09: Diaz-Mejia JJ, Babu M, Emili A (2009). "Computational and experimental approaches to chart the Escherichia coli cell-envelope-associated proteome and interactome." FEMS Microbiol Rev 33(1);66-97. PMID: 19054114
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