Sequence analyses reveal that a TPR–DP module, surrounded by recombinable flanking introns, could be at the origin of eukaryotic Hop and Hip TPR–DP domains and prokaryotic GerD proteins

Laboratorio de Biología Molecular, Escuela de Biología, Universidad Industrial de Santander, Apartado Aéreo 678, Bucaramanga, Colombia.
Cell Stress and Chaperones (Impact Factor: 3.16). 12/2008; 14(3):281-9. DOI: 10.1007/s12192-008-0083-8
Source: PubMed


The co-chaperone Hop [heat shock protein (HSP) organising protein] is known to bind both Hsp70 and Hsp90. Hop comprises three repeats of a tetratricopeptide repeat (TPR) domain, each consisting of three TPR motifs. The first and last TPR domains are followed by a domain containing several dipeptide (DP) repeats called the DP domain. These analyses suggest that the hop genes result from successive recombination events of an ancestral TPR-DP module. From a hydrophobic cluster analysis of homologous Hop protein sequences derived from gene families, we can postulate that shifts in the open reading frames are at the origin of the present sequences. Moreover, these shifts can be related to the presence or absence of biological function. We propose to extend the family of Hop co-chaperons into the kingdom of bacteria, as several structurally related genes have been identified by hydrophobic cluster analysis. We also provide evidence of common structural characteristics between hop and hip genes, suggesting a shared precursor of ancestral TPR-DP domains.

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Available from: Jorge Hernández, May 02, 2015
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    • "It contains all functional domains of animal HIP proteins, including a conserved N-terminal dimerization domain, a highly acidic domain, three tetratricopeptide repeats (TPR), a charged region, a series of degenerate glycine-glycine-methionineproline (GGMP) tandem repeats, and a C-terminal region with limited similarity to yeast stress–induced protein Sti1 and its ortholog HOP/p60 (Fig. 1A). The TPR domain of animal HIP proteins may mediate interactions with heat shock proteins (Carrello et al. 2004; Hernández Torres et al. 2009; Velten et al. 2000), while the exact function of the GGMP repeats is unclear (Boorstein et al. 1994). HIP homologs are present in protists, plants, and animals (Supplementary Table 1) but absent in fungi and algae. "
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