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76  structures 3052  species 0  interactions 3550  sequences 32  architectures

Family: HK (PF02110)

Summary: Hydroxyethylthiazole kinase family

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This is the Wikipedia entry entitled "Hydroxyethylthiazole kinase". More...

Hydroxyethylthiazole kinase Edit Wikipedia article

hydroxyethylthiazole kinase
EC number2.7.1.50
CAS number9026-56-6
IntEnzIntEnz view
ExPASyNiceZyme view
MetaCycmetabolic pathway
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO
Hydroxyethylthiazole kinase family
PDB 1c3q EBI.jpg
crystal structure of native thiazole kinase in the monoclinic form
Pfam clanCL0118

In enzymology, a hydroxyethylthiazole kinase (EC is an enzyme that catalyzes the chemical reaction

ATP + 4-methyl-5-(2-hydroxyethyl)thiazole ADP + 4-methyl-5-(2-phosphonooxyethyl)thiazole

Thus, the two substrates of this enzyme are ATP and 4-methyl-5-(2-hydroxyethyl)thiazole, whereas its two products are ADP and 4-methyl-5-(2-phosphonooxyethyl)thiazole.

This enzyme belongs to the family of transferases, specifically those transferring phosphorus-containing groups (phosphotransferases) with an alcohol group as acceptor. The systematic name of this enzyme class is ATP:4-methyl-5-(2-hydroxyethyl)thiazole 2-phosphotransferase. Other names in common use include hydroxyethylthiazole kinase (phosphorylating), and 4-methyl-5-(beta-hydroxyethyl)thiazole kinase. This enzyme participates in thiamine metabolism. Thiamine pyrophosphate (TPP), a required cofactor for many enzymes in the cell, is synthesised de novo in Salmonella typhimurium.[1]

In Saccharomyces cerevisiae, hydroxyethylthiazole kinase expression is regulated at the mRNA level by intracellular thiamin pyrophosphate.[2]

Structural studies

As of late 2007, 6 structures have been solved for this class of enzymes, with PDB accession codes 1C3Q, 1EKK, 1EKQ, 1ESJ, 1ESQ, and 1V8A.


  1. ^ Petersen LA, Downs DM (August 1997). "Identification and characterization of an operon in Salmonella typhimurium involved in thiamine biosynthesis". J. Bacteriol. 179 (15): 4894–900. PMC 179339. PMID 9244280.
  2. ^ Nosaka K, Nishimura H, Kawasaki Y, Tsujihara T, Iwashima A (December 1994). "Isolation and characterization of the THI6 gene encoding a bifunctional thiamin-phosphate pyrophosphorylase/hydroxyethylthiazole kinase from Saccharomyces cerevisiae". J. Biol. Chem. 269 (48): 30510–6. PMID 7982968.

Further reading

  • Lewin LM & Brown GM (1961). "The biosynthesis of thiamine. III. Mechanism of enzymatic formation of the pyrophosphate ester of 2-methyl-4-amino-5-hydroxymethylpyrimidine". J. Biol. Chem. 236: 2768–2771.
This article incorporates text from the public domain Pfam and InterPro: IPR000417

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Hydroxyethylthiazole kinase family Provide feedback

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Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR000417

Most microorganisms and plants can synthesise thiamin de novo [ PUBMED:19348578 ]. In this de novo pathway, the thiazole and pyrimidine moieties of thiamin are made separately and coupled together to form thiamin phosphate. For the thiazole moiety, 4-methyl-5-(2-hydroxyethyl)thiazole (THZ), the key salvage step is phosphorylation to give 4-methyl-5-(2-phosphonooxyethyl)thiazole (THZ-P). The enzyme hydoxyethylthiazole kinase ( EC ) is responsible for this step. Hydoxyethylthiazole kinase is encoded by thiM in Escherichia coli [ PUBMED:2542220 ] and other bacteria, and by the C-terminal region of bifunctional proteins in some cases, such as Saccharomyces cerevisiae, in which the N-terminal domain corresponds to the bacterial thiamine-phosphate pyrophosphorylase ( EC ), ThiE [ PUBMED:7982968 , PUBMED:20968298 ].

The Arabidopsis and maize genomes encode homologues of ThiM [ PUBMED:23816351 ].

Gene Ontology

The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.

Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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Pfam Clan

This family is a member of clan Ribokinase (CL0118), which has the following description:

All of these enzymes are phosphotransferases that have an alcohol group as an acceptor (EC:2.7.1.-). However, 4-amino-5-hydroxymethyl-2-methylpyrimidine phosphate kinase (HMPP kinase) catalyses two phosphorylation reactions: one to a hydroxymethyl group of hydroxymethyl pyrimidine (HMP) and the second to the phosphomethyl group of HMPP [1]. The common structural feature for the enzymes in this superfamily is a central eight-stranded sheet that is flanked by eight structurally conserved helices, five on one side and three on the other [1]. The active site is located in a shallow groove along one edge of the sheet, with the phosphate acceptor hydroxyl group and -phosphate of ATP close together in the middle of the groove, and substrate and ATP binding at the ends [1].

The clan contains the following 5 members:

ADP_PFK_GK Carb_kinase HK PfkB Phos_pyr_kin


We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database (reference proteomes) using the family HMM. We also generate alignments using four representative proteomes (RP) sets and the UniProtKB sequence database. More...

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Curation and family details

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Seed source: IPR000417
Previous IDs: none
Type: Domain
Sequence Ontology: SO:0000417
Author: Mian N , Bateman A
Number in seed: 8
Number in full: 3550
Average length of the domain: 236.90 aa
Average identity of full alignment: 36 %
Average coverage of the sequence by the domain: 75.08 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 57096847 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 20.1 20.1
Trusted cut-off 20.1 20.1
Noise cut-off 20.0 20.0
Model length: 246
Family (HMM) version: 17
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For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the HK domain has been found. There are 76 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein sequence.

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