Protein Family Models

This domain is found Bacteriophage lambda minor tail protein G and related sequences [1]. The construction of phage tails involves a stage of tail-tube formation, and tail-tube polymerisation requires two additional proteins, gpG and gpGT. The open reading frames, ORFs, for gpG and gpGT are overlapping and are related by a programmed translational frameshift. During virion morphogenesis, gpG is expressed in large amounts, and about 3.5% of the time, a -1 translational frameshift leads to the production of the larger fusion protein, gpGT. The correct ratio of gpG to gpGT, as determined by the frequency of frameshifting, is crucial for tail assembly. Since gpG accumulates to high levels during a lambda infection and yet is not found in mature phage particles it is believed to act as a chaperone [2]. [1]. 8230192. A programmed translational frameshift is required for the synthesis of a bacteriophage lambda tail assembly protein. Levin ME, Hendrix RW, Casjens SR;. J Mol Biol 1993;234:124-139. [2]. 23542344. A conserved spiral structure for highly diverged phage tail assembly chaperones. Pell LG, Cumby N, Clark TE, Tuite A, Battaile KP, Edwards AM, Chirgadze NY, Davidson AR, Maxwell KL;. J Mol Biol. 2013;425:2436-2449. (from Pfam)

Date:

2024-10-16

This HMM describes a family of bacteriophage proteins including G of phage lambda. This protein has been described as undergoing a translational frameshift at a Gly-Lys dipeptide near the C-terminus of protein G from phage lambda, with about 4 % efficiency, to produce the longer tail assembly protein G-T. The Lys of the Gly-Lys pair is the conserved second-to-last residue of seed alignment for this family. Subsequent work has shown that apparent -1 frameshift motifs are a regular feature the overlap regions of analogous gpG and gpGT tail assembly protein gene pairs found in the region between the phage major tail protein (V) and the phage tail tape measure protein (H).

Gene:

gpG

Date:

2024-07-23

phage minor tail protein G promotes tail assembly by creating a scaffold for the tail tube proteins

Date:

2020-05-28