Protein Family Models

Date:

2024-08-14

Initiation of packaging of double-stranded viral DNA involves the specific interaction of the prohead with viral DNA in a process mediated by a phage-encoded terminase protein. The terminase enzymes are usually hetero-oligomers composed of a small and a large subunit. This region is found on the large subunit and possess an endonuclease and ATPase activity that require Mg2+ and a neutral or slightly basic reaction. This region is also found in bacterial sequences [1,2]. [1]. 10930407. Functional analysis of the terminase large subunit, G2P, of Bacillus subtilis bacteriophage SPP1. Gual A, Camacho AG, Alonso JC;. J Biol Chem 2000;275:35311-35319. [2]. 1548711. Molecular analysis of the Bacillus subtilis bacteriophage SPP1 region encompassing genes 1 to 6. The products of gene 1 and gene 2 are required for pac cleavage. Chai S, Bravo A, Luder G, Nedlin A, Trautner TA, Alonso JC;. J Mol Biol 1992;224:87-102. (from Pfam)

Date:

2024-10-16

This entry represents the N-terminal domain of terminase large subunits found in a variety of the Caudovirales and prophage regions of bacterial genomes. It includes the terminase large subunit of Bacteriophage T4 (terminase gene 17, Gp17) [1,3]. Homologues are also found in Gene Transfer Agents (GTA) [2], including ORFg2 (RCAP_rcc01683) of the GTA of Rhodobacter capsulatus (Rhodopseudomonas capsulata) [see Fig.1, in 4]. [1]. 12235385. Sequence analysis of bacteriophage T4 DNA packaging/terminase genes 16 and 17 reveals a common ATPase center in the large subunit of viral terminases. Mitchell MS, Matsuzaki S, Imai S, Rao VB;. Nucleic Acids Res. 2002;30:4009-4021. [2]. 11382219. The gene transfer agent of Rhodobacter capsulatus and "constitutive transduction" in prokaryotes. Lang AS, Beatty JT;. Arch Microbiol. 2001;175:241-249. [3]. 12466275. Isolation and characterization of T4 bacteriophage gp17 terminase, a large subunit multimer with enhanced ATPase activity. Baumann RG, Black LW;. J Biol Chem. 2003;278:4618-4627. [4]. 12399927. Evolutionary implications of phylogenetic analyses of the gene transfer agent (GTA) of Rhodobacter capsulatus. Lang AS, Taylor TA, Beatty JT;. J Mol Evol. 2002;55:534-543. (from Pfam)

Date:

2024-10-16

PBSX family phage terminase large subunit acts as an ATP driven molecular motor necessary for viral DNA translocation into empty capsids and as an endonuclease that cuts the viral genome to initiate and to end a packaging reaction

Date:

2022-02-22

This HMM detects members of a highly divergent family of the large subunit of phage terminase. All members are encoded by phage genomes or within prophage regions of bacterial genomes. This is a distinct family from PF03354.

Date:

2019-09-10