Proteogenomic refinement of the Neomegalonema perideroedes genome annotation

Neomegalonema perideroedes (formerly Meganema perideroedes) str. G1 is the type strain and only described isolate of the genus Neomegalonema (formerly Meganema). N. perideroedes is distinguished by the ability to accumulate high amounts of polyhydroxyalkanoates and has been associated with bulking problems in wastewater treatment plants due to its filamentous morphology. In 2013, its genome was sequenced as part of the Genomic Encyclopedia of Bacteria and Archaea (GEBA), which aims to improve the sequencing coverage of the poorly represented regions of the bacterial and archaeal branches of the tree of life. As N. perideroedes str. G1 is relatively distantly related to well described species – being the only sequenced member of its proposed family - the in silico prediction of genes by nucleotide homology to reference genes might be less reliable. The aim of this study was to improve the genome annotation by usage of proteomic data. Besides the identification of novel and overlooked genes, the N-terminal cleavage pattern and the differences between databases were considered. Proteogenomic approaches, such as is described here, complements the GEBA initiative well - by providing important refinement of reference genome annotations.