Discovery of a small protein factor involved in the coordinated degradation of phycobilisomes in cyanobacteria
Vanessa Krauspe, Matthias Fahrner, Philipp Spät, Claudia Steglich, Nicole Frankenberg‐Dinkel, Boris Maček, Oliver Schilling, Wolfgang R. Hess
Abstract
Significance During genome analysis, genes encoding small proteins are frequently neglected. Accordingly, small proteins have remained underinvestigated in all domains of life. Based on a previous systematic search for such genes, we present the functional analysis of the 66 amino acids protein NblD in a photosynthetic cyanobacterium. We show that NblD plays a crucial role during the coordinated dismantling of phycobilisome light-harvesting complexes. This disassembly is triggered when the cells become starved for nitrogen, a condition that frequently occurs in nature. Similar to NblA that tags phycobiliproteins for proteolysis, NblD binds to phycocyanin polypeptides but has a different function. The results show that, even in a well-investigated process, crucial new players can be discovered if small proteins are taken into consideration.