title: Extended N-terminal region of the essential phosphorelay signaling protein Ypd1 from Cryptococcus neoformans contributes to structural stability, phosphostability and binding of calcium ions.
abstract: Rapid response to external stimuli is crucial for survival and proliferation of microorganisms. Pathogenic fungi employ histidine-to-aspartate multistep phosphorelay systems to respond to environmental stress, progress through developmental stages and to produce virulence factors. Because these His-to-Asp phosphorelay systems are not found in humans, they are potential targets for the development of new antifungal therapies. Here we report the characterization of the histidine phosphotransfer (HPt) protein Ypd1 from the human fungal pathogen Cryptococcus neoformans Results from this study demonstrate that CnYpd1 indeed functions as a phosphorelay protein in vitro, and that H138 is confirmed as the site of phosphorylation. We found that CnYpd1 exhibits unique characteristics in comparison to other histidine phosphotransfer proteins, such as an extended N-terminal amino acid sequence, which we find contributes to structural integrity, a longer phosphorylated life time and the ability to bind calcium ions.
authors.affiliation: Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK 73019, USA.
authors.forename: Emily N
authors.initials: EN
authors.lastname: Kennedy
authors.affiliation: Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK 73019, USA.
authors.forename: Smita K
authors.initials: SK
authors.lastname: Menon
authors.affiliation: Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK 73019, USA awest@ou.edu.
authors.forename: Ann H
authors.initials: AH
authors.lastname: West
mesh_terms: D000595:Amino Acid Sequence; D002118:Calcium / Q000378:metabolism*; D002413:Cations, Divalent / Q000378:metabolism*; D003455:Cryptococcus neoformans / Q000201:enzymology*; D006639:Histidine / Q000378:metabolism; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011485:Protein Binding; D000072417:Protein Domains; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D055550:Protein Stability
chemical_list: D002413:Cations, Divalent; D006639:Histidine; D011494:Protein Kinases; D002118:Calcium
keywords: Cryptococcus neoformans; His-to-Asp phosphorelay systems; Histidine-containing (HPt) phosphotransfer protein; Ypd1; signal transduction; two-component system