Bdellovibrio bacteriovorus phosphoglucose isomerase structures reveal novel rigidity in the active site of a selected subset of enzymes upon substrate binding. Issue 8 (11th August 2021)

• Record Type: Journal Article
• Authors: Meek, R. W.; Cadby, I. T.; Lovering, A. L.
• Is Part Of: Open biology. Volume 11:Issue 8(2021)
• Publication Date: 2021-08-11
• Subjects: Bdellovibrio bacteriovorus HD100 -- phosphoglucose isomerase -- glucose-6-phosphate -- fructose-6-phosphate -- glycolysis -- metabolism; Biology -- Periodicals; 570
• DOI: 10.1098/rsob.210098
• Languages: English
• ISSNs: 2046-2441

Abstract

Abstract : Abstract : Glycolysis and gluconeogenesis are central pathways of metabolism across all domains of life. A prominent enzyme in these pathways is phosphoglucose isomerase (PGI), which mediates the interconversion of glucose-6-phosphate and fructose-6-phosphate. The predatory bacterium Bdellovibrio bacteriovorus leads a complex life cycle, switching between intraperiplasmic replicative and extracellular 'hunter' attack-phase stages. Passage through this complex life cycle involves different metabolic states. Here we present the unliganded and substrate-bound structures of the B. bacteriovorus PGI, solved to 1.74 Å and 1.67 Å, respectively. These structures reveal that an induced-fit conformational change within the active site is not a prerequisite for the binding of substrates in some PGIs. Crucially, we suggest a phenylalanine residue, conserved across most PGI enzymes but substituted for glycine in B. bacteriovorus and other select organisms, is central to the induced-fit mode of substrate recognition for PGIs. This enzyme also represents the smallest conventional PGI characterized to date and probably represents the minimal requirements for a functional PGI.