In Silico Horizontal Gene Transfer and Functional Motif in Gshf Protein of Listeria Monocytogenes

Srinivas V, Kreft J, Gopal S., In silico horizontal gene transfer and functional motif in GshF protein of Listeria monocytogenes, Online J Bioinform, 13(1):14-26, 2012. Glutathione synthesis, a two step process in Listeria monocytogenes, is performed by a single Glutathione fusion protein (GshF). GshF comprises 776 amino acids with N terminal gammaglutamylcysteine ligase (GshA) and C terminal ATP grasp dependent domains. Amino acids 338 to 580 were horizontally gene transferred through a symbiotic relationship within the host and other bacteria. Flipping of unstructured proteins in eukaryotes during host pathogen interaction may have triggered fusion. In this study, a novel motif KPKX|S/T|TN in L. monocytogenes EGDe was identified in GshF/GshAB (Glutathione biosynthesis bifunctional protein) conserved in proteobacteria, bacteriodetes and firmicutes. The motif was present in the B-loop and residues were exposed. L. monocytogenes EGD-e motif consisted of phosphorylation residues which could regulate ligase activity.