Protein Family Models

This entry represents the ferredoxin-like domain found at the N-terminal of ThiI proteins (NFLD) [1-3]. ThiI is responsible for the formation of the modified base S(4)U (4-thiouridine) found at position 8 in some prokaryotic tRNA. This domain connects the C-terminal catalytic PP-loop pyrophosphatase domain with the THUMP (Pfam:PF02926). NFLD and the THUMP domains jointly form the tRNA-binding surface shaped like a channe which may be of particular importance in ThiI for the correct orientation and distance between residues involved in RNA binding and the active site of the enzyme [2,4]. Paper describing PDB structure 1vbk. [1]. 17183176. Purification, crystallization and preliminary crystallographic analysis of the putative thiamine-biosynthesis protein PH1313 from Pyrococcus horikoshii OT3. Sugahara M, Murai S, Sugahara M, Kunishima N;. Acta Crystallogr Sect F Struct Biol Cryst Commun. 2007;63:56-58. Paper describing PDB structure 2c5s. [2]. 16343540. Crystal structure of Bacillus anthracis ThiI, a tRNA-modifying enzyme containing the predicted RNA-binding THUMP domain. Waterman DG, Ortiz-Lombardia M, Fogg MJ, Koonin EV, Antson AA;. J Mol Biol. 2006;356:97-110. Paper describing PDB structure 4kr6. [3]. 24705700. Crystal structure of a 4-thiouridine synthetase-RNA complex reveals specificity of tRNA U8 modification. Neumann P, Lakomek K, Naumann PT, Erwin WM, Lauhon CT, Ficner R;. Nucleic Acids Res. 2014;42:6673-6685. [4]. 36833309. Transfer RNA Modification Enzymes with a Thiouridine Synthetase, Methyltransferase and Pseudouridine Synthase (THUMP) Domain and the Nucleosides They Produce in tRNA. Hori H;. Genes (Basel). . TRUNCATED at 1650 bytes (from Pfam)

Date:

2024-10-16

The THUMP domain is named after after thiouridine synthases, methylases and PSUSs [1]. The THUMP domain consists of about 110 amino acid residues. This domain is found in many tRNA modification enzymes classified into five types, namely 4-thiouridine synthetase, deaminase, methyltransferase, a partner protein of acetyltransferase and pseudouridine synthase [3]. The structure of ThiI reveals that the THUMP has a fold unlike that of previously characterised RNA-binding domains [2-3] and was first predicted to function by delivering a variety of RNA modification enzymes to their targets [1]. Studies performed in tRNA 4-thiouridine synthetase, tRNA methyltransferases and tRNA deaminase suggest that the THUMP domain captures the 3'-end of RNA but in some cases this is not applicable due to the modification patterns observed in tRNA [3]. Several THUMP-related proteins are also involved in other RNAs modifications, such as rRNA modification [3]. [1]. 11295541. THUMP - a predicted RNA-binding domain shared by 4-thiouridine, pseudouridine synthases and RNA methylases. Aravind L, Koonin EV;. Trends Biochem Sci 2001;26:215-217. [2]. 16343540. Crystal structure of Bacillus anthracis ThiI, a tRNA-modifying enzyme containing the predicted RNA-binding THUMP domain. Waterman DG, Ortiz-Lombardia M, Fogg MJ, Koonin EV, Antson AA;. J Mol Biol. 2006;356:97-110. [3]. 36833309. Transfer RNA Modification Enzymes with a Thiouridine Synthetase, Methyltransferase and Pseudouridine Synthase (THUMP) Domain and the Nucleosides They Produce in tRNA. Hori H;. Genes (Basel). 2023;14:382. (from Pfam)

Date:

2024-10-16

ThiI is required for thiazole synthesis, required for thiamine biosynthesis [1]. [1]. 9209060. Characterization of thiI, a new gene involved in thiazole biosynthesis in Salmonella typhimurium. Webb E, Claas K, Downs DM;. J Bacteriol 1997;179:4399-4402. (from Pfam)

Date:

2024-10-16

The ThiI protein of Escherichia coli is a bifunctional protein in which most of the length of the protein is responsible for sulfurtransferase activity in 4-thiouridine modification to tRNA (EC 2.8.1.4 - see model TIGR00342). This rhodanese-like C-terminal domain, by itself, is able to synthesize the thiazole moiety during thiamin biosynthesis. Note that the invariant Cys residue in this domain is unusual in being required for both activities of the bifunctional ThiI protein.

Gene:

thiI

Date:

2024-06-27

Members of this protein family are the sulfurtransferase ThiI, involved in 4-thiouridine modification of tRNA. This protein often is bifunctional, with genetically separable activities, where the C-terminal rhodanese-like domain (residues 385 to 482 in E. coli ThiI), a domain not included in this model, is sufficient to synthesize the thiazole moiety of thiamine (see TIGR04271). Note that ThiI, because of its role in tRNA modification, may occur in species (such as Mycoplasma genitalium) that lack de novo thiamine biosynthesis.

Gene:

thiI

Date:

2023-04-18