Phenotypic and proteomic analysis of positively regulated gellan biosynthesis pathway in Sphingomonas elodea

• Published in: Animal cells and systems Vol. 21; no. 2; pp. 115 - 123
• Main Authors: Lee, Soo Youn, Ahn, Ji-Young, Kim, Mihye, Sekhon, Simranjeet Singh, Cho, Sung-Jin, Kim, Young-Chang, Kim, Yang-Hoon
• Format: Journal Article
• Language: English
• Published: Korea (South) Taylor & Francis 04.03.2017; Taylor & Francis Ltd; 한국통합생물학회
• Subjects: Biosynthesis; gel cluster; Gellan biosynthesis; Metabolites; phenotypic analysis; Proteins; proteome analysis; Sphingomonas; Sphingomonas elodea; Sugar; 생물학; Sphingomonas elodea; proteome analysis; gel cluster; phenotypic analysis; Gellan biosynthesis
• ISSN: 1976-8354; 2151-2485
• DOI: 10.1080/19768354.2017.1290678

Sphingomonas elodea is a Gram-negative bacterium capable of producing 'gellan gum' exopolysaccharide that is the most extensively studied expolysaccharides of microbial origin. In this study, we investigated the phenotypic and proteomic alterations in S. elodea by homogeneously expressing both gelA and gelN involved in positive regulation and extracellular secretion of metabolites in gellan biosynthesis, respectively. Expression of six histidine-tagged GelA and GelN was determined by Western blot analysis. Successful expression of GelA and GelN resulted in both morphological changes of colonies and enhanced secretion of gellan into the growth medium (GelA, 21.2% more and GelN, 48.3% more) overexpressed compared to the wile-type. Comparative two-dimensional gel electrophoresis analysis revealed a differential proteome expression in S. elodea overexpressing GelA and GelN. Proteins up- or down-regulated by GelA and GelN overexpression were found to be mainly sugar transportation proteins, two-component regulatory proteins, and proteins involved in secretion pathways. The results suggest that the effect of GelA and GelN overexpression on gellan biosynthesis might be mainly caused by increased transportation of sugar units or enhanced exportation of gellan.