Virtual 2-D map of the fungal proteome

Abstract

The molecular weight and isoelectric point (pI) of the proteins plays important role in the cell. Depending upon the shape, size, and charge, protein provides its functional role in different parts of the cell. Therefore, understanding to the knowledge of their molecular weight and charges is (pI) is very important. Therefore, we conducted a proteome-wide analysis of protein sequences of 689 fungal species (7.15 million protein sequences) and construct a virtual 2-D map of the fungal proteome. The analysis of the constructed map revealed the presence of a bimodal distribution of fungal proteomes. The molecular mass of individual fungal proteins ranged from 0.202 to 2546.166 kDa and the predicted isoelectric point (pI) ranged from 1.85 to 13.759 while average molecular weight of fungal proteome was 50.98 kDa. A non-ribosomal peptide synthase (RFU80400.1) found in Trichoderma arundinaceum was identified as the largest protein in the fungal kingdom. The collective fungal proteome is dominated by the presence of acidic rather than basic pI proteins and Leu is the most abundant amino acid while Cys is the least abundant amino acid. Aspergillus ustus encodes the highest percentage (76.62%) of acidic pI proteins while Nosema ceranae was found to encode the highest percentage (66.15%) of basic pI proteins. Selenocysteine and pyrrolysine amino acids were not found in any of the analysed fungal proteomes. Although the molecular weight and pI of the protein are of enormous important to understand their functional roles, the amino acid compositions of the fungal protein will enable us to understand the synonymous codon usage in the fungal kingdom. The small peptides identified during the study can provide additional biotechnological implication.

Virtual 2D mapping of the viral proteome reveals host-specific modality distribution of molecular weight and isoelectric point

“…The average isoelectric point of the virus proteome is in the acidic pI range ( pI 6.89), which is similar to average pI of the nuclear-encoded plant and fungal proteomes 27 , 28 . The average algal virus proteome had a pI of 7.08 and the vertebrate viral proteome had a pI of 7.09, both of which are in the basic range.…”

“…The average number of amino acids per protein sequence in fungal and land plant viral proteomes were found to be 882.464 and 405.099, respectively. Notably, the average number of amino acids per protein in the nuclear-encoded (not from chloroplast or mitochondrial encoded) plant proteome was 424.34, while the nuclear-encoded (not from chloroplast) proteome of fungi was 459.319 27 , 28 . Interestingly, we found that fungal viruses encode larger proteins than the nuclear encoded proteins of its host.…”

“…Viruses were also found to encode small peptides. The smallest peptide of the virus kingdom was revealed as the penta-peptide, M-S-S-T-T, while the smallest peptide encoded in the plant kingdom is a tetra peptide, M-I-M-F, and a dipeptide, M-V, in the fungal kingdom 27 , 28 . It is interesting to study the functional aspects of small, viral peptides and their molecular activities in host cells have been determined to perform several biological functions 29 , 30 .…”

“…The average amino acid composition of virus proteome indicated that Leu (8.556%) is the most abundant and Trp (1.274%) is the least abundant amino acid, respectively. Leu is also the most abundant amino acid in the nuclear-encoded plant (9.62%) and fungal (9.115%) proteome 27 , 28 . While Trp (1.28%) is the least abundant amino acid in the nuclear-encoded plant kingdom proteome, Cys (1.267%) is the least abundant amino acid in the nuclear-encoded fungal kingdom proteome 27 , 28 .…”

“…Leu is also the most abundant amino acid in the nuclear-encoded plant (9.62%) and fungal (9.115%) proteome 27 , 28 . While Trp (1.28%) is the least abundant amino acid in the nuclear-encoded plant kingdom proteome, Cys (1.267%) is the least abundant amino acid in the nuclear-encoded fungal kingdom proteome 27 , 28 . Cysteine forms disulphide bonds in proteins and provides conformational stability.…”