BADASP: predicting functional specificity in protein families using ancestral sequences

Edwards RJ & Shields DC (2005): BADASP: predicting functional specificity in protein families using ancestral sequences. Bioinformatics 21(22):4190-1.

Abstract

SUMMARY: Burst After Duplication with Ancestral Sequence Predictions (BADASP) is a software package for identifying sites that may confer subfamily-specific biological functions in protein families following functional divergence of duplicated proteins. A given protein phylogeny is grouped into subfamilies based on orthology/paralogy relationships and/or user definitions. Ancestral sequences are then predicted from the sequence alignment and the functional specificity is calculated using variants of the Burst After Duplication method, which tests for radical amino acid substitutions following gene duplications that are subsequently conserved. Statistics are output along with subfamily groupings and ancestral sequences for an easy analysis with other packages.

AVAILABILITY: BADASP is freely available from http://www.bioinformatics.rcsi.ie/~redwards/badasp/

PMID: 16159912

Correlation of probiotic Lactobacillus salivarius growth phase with its cell wall-associated proteome

Kelly P, Maguire PB, Bennett M, Fitzgerald DJ, Edwards RJ, Thiede B, Treumann A, Collins JK, O’Sullivan GC, Shanahan F & Dunne C (2005): Correlation of probiotic Lactobacillus salivarius growth phase with its cell wall-associated proteome. FEMS Microbiol. Lett. 252(1):153-159.

Abstract

Lactobacillus salivarius subsp. salivarius UCC118 is a probiotic bacterium that was originally isolated from human intestinal tissues and was subsequently shown in a pilot study to alleviate symptoms associated with mild-moderate Crohn’s disease. Strain UCC118 can adhere to animal and human intestinal tissue, and to both healthy and inflamed ulcerative colitis mucosa, irrespective of location in the gut. In this study, an enzymatic technique has been combined with proteomic analysis to correlate bacterial growth phase with the presence of factors present in the cell wall of the bacterium. Using PAGE electrophoresis, it was determined that progression from lag to log to stationary growth phases in vitro correlated with increasing prominence of an 84kD protein associated with in vitro adherence ability. Isolated proteins from the 84kD band region were further separated by two-dimensional electrophoresis, resolving this band into 20 individual protein spots at differing isoelectric points. The protein moieties were excised, trypsin digested and subjected to tandem mass spectrometry. The observed proteins are analogous to those reported to be associated with the Listeria monocytogenes cell-wall proteome, and include DnaK, Ef-Ts and pyruvate kinase. These data suggest that at least some of the beneficial attributes of probiotic lactobacilli, and in particular this strain, may be due to nonpathogenic mimicry of pathogens and potentially be mediated through a form of attenuated virulence.

PMID: 16214296

Tandem repeat copy-number variation in protein-coding regions of human genes

O’Dushlaine CT, Edwards RJ, Park SD & Shields DC (2005): Tandem repeat copy-number variation in protein-coding regions of human genes. Genome Biol. 6(9):R69.

Abstract

BACKGROUND: Tandem repeat variation in protein-coding regions will alter protein length and may introduce frameshifts. Tandem repeat variants are associated with variation in pathogenicity in bacteria and with human disease. We characterized tandem repeat polymorphism in human proteins, using the UniGene database, and tested whether these were associated with host defense roles.

RESULTS: Protein-coding tandem repeat copy-number polymorphisms were detected in 249 tandem repeats found in 218 UniGene clusters; observed length differences ranged from 2 to 144 nucleotides, with unit copy lengths ranging from 2 to 57. This corresponded to 1.59% (218/13,749) of proteins investigated carrying detectable polymorphisms in the copy-number of protein-coding tandem repeats. We found no evidence that tandem repeat copy-number polymorphism was significantly elevated in defense-response proteins (p = 0.882). An association with the Gene Ontology term ‘protein-binding’ remained significant after covariate adjustment and correction for multiple testing. Combining this analysis with previous experimental evaluations of tandem repeat polymorphism, we estimate the approximate mean frequency of tandem repeat polymorphisms in human proteins to be 6%. Because 13.9% of the polymorphisms were not a multiple of three nucleotides, up to 1% of proteins may contain frameshifting tandem repeat polymorphisms.

CONCLUSION: Around 1 in 20 human proteins are likely to contain tandem repeat copy-number polymorphisms within coding regions. Such polymorphisms are not more frequent among defense-response proteins; their prevalence among protein-binding proteins may reflect lower selective constraints on their structural modification. The impact of frameshifting and longer copy-number variants on protein function and disease merits further investigation.

PMID: 16086851

Tyrosine phosphorylation of myosin heavy chain during skeletal muscle differentiation: an integrated bioinformatics approach

Harney DF, Butler RK & Edwards RJ (2005): Tyrosine phosphorylation of myosin heavy chain during skeletal muscle differentiation: an integrated bioinformatics approach. Theor. Biol. Med. Model. 2(1):12.

Abstract

BACKGROUND: Previously it has been shown that insulin-mediated tyrosine phosphorylation of myosin heavy chain is concomitant with enhanced association of C-terminal SRC kinase during skeletal muscle differentiation. We sought to identify putative site(s) for this phosphorylation event.

RESULTS: A combined bioinformatics approach of motif prediction and evolutionary and structural analyses identified tyrosines163 and 1856 of the skeletal muscle heavy chain as the leading candidate for the sites of insulin-mediated tyrosine phosphorylation.

CONCLUSION: Our work is suggestive that tyrosine phosphorylation of myosin heavy chain, whether in skeletal muscle or in platelets, is a significant event that may initiate cytoskeletal reorganization of muscle cells and platelets. Our studies provide a good starting point for further functional analysis of MHC phosphor-signalling events within different cells.

PMID: 15790426