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Hashem, A.

Publications and source records attributed to Hashem, A..

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Genomics, Molecular and Evolutionary Perspective of NAC Transcription Factors

NAC (NAM, ATAF1,2, and CUC2) transcription factors are one of the largest transcription factor families found in plants and are involved in diverse developmental and signalling events. Despite the availability of comprehensive genomic information from diverse plant species, the basic genomic, biochemical, and evolutionary details of NAC TFs have not been established. Therefore, NAC TFs family proteins from 160 plant species were analyzed in the current study. The analysis, among other things, identified the first algal NAC TF in the Charophyte, Klebsormidium flaccidum. Furthermore, our analysis revealed that NAC TFs are membrane bound and contain monopartite, bipartite, and multipartite nuclear localization signals. NAC TFs were also found to encode a novel chimeric protein domain and are part of a complex interactome network. Synonymous codon usage is absent in NAC TFs and it appears that they have evolved from orthologous ancestors and undergone significant duplication events to give rise to paralogous NAC TFs.

genomics

The Molecular Mass and Isoelectric Point of Plant Proteomes

A proteomic analysis of proteomes from 145 plant species revealed a pI range of 1.99 (epsin) to 13.96 (hypothetical protein). The molecular mass of the plant proteins ranged from 0.54 to 2236.8 kDa. A putative Type-I polyketide synthase (22244 amino acids) in Volvox carteri was found to be the largest protein in the plant kingdom and was not found in higher plant species. Titin (806.46 kDa) and misin/midasin (730.02 kDa) were the largest proteins identified in higher plant species. The pI and molecular weight of the plant proteome exhibited a trimodal distribution. An acidic pI (56.44% of proteins) was found to be predominant over a basic pI (43.34% of proteins) and the abundance of acidic pI proteins was higher in unicellular algae species relative to multicellular higher plants. In contrast, the seaweed, Porphyra umbilicalis, possesses a higher proportion of basic pI proteins (70.09%). Plant proteomes were also found to contain the amino acid, selenocysteine (Sec), which is the first report of the presence of this amino acid in plants. Additionally, plant proteomes also possess ambiguous amino acids Xaa (unknown), Asx (asparagine or aspartic acid), Glx (glutamine or glutamic acid), and Xle (leucine or isoleucine) as well.

plant biology