A comprehensive study of highly repetitive WD40 proteins in cyanobacteria

Abstract

The WD40 repeat-containing proteins are ancient proteins regulating various cellular and biological processes in eukaryotes. WD40 proteins are extensively studied in eukaryotes, and their genome-wide characterisation has revealed their hidden potential. On the contrary, in-depth taxonomic and functional description of WD40 proteins in prokaryotes, particularly in cyanobacteria, remains largely unexplored. In this study, we have comprehensively analysed cyanobacterial WD40 proteins and detailed comparisons among different cyanobacterial orders. About 7000 WD40 proteins were identified in all six cyanobacterial orders accounting for 22–43 % of all WD40s. While their abundance was less in Chroococcales, Pleurocapsales and, Stigonematales, the WD40s were profoundly present in Nostcales and Oscillatoriales, exhibiting multifarious functions such as cell signalling, transcription factors, catalytic enzymes and scaffold etc. Current systemic analysis showed that most WD40 proteins contain multiple WD40 domains, as indicated by their repeat numbers and average confidence scores. The observation also indicated that most WD40 proteins have complex hydrogen bond networks. Their taxonomic distribution and gene neighbourhood analysis revealed topical or newly repeated duplication events form most WD40s. Further, the studies confirmed that the recently formed WD40 proteins are highly repetitive with higher structural stability. Overall, the result of this study has described an assembly of cyanobacterial WD40 proteins and highlighting their evolution, distribution and probable functions.