title: Sequence-, structure-, and dynamics-based comparisons of structurally homologous CheY-like proteins.
abstract: We recently introduced a physically based approach to sequence comparison, the property factor method (PFM). In the present work, we apply the PFM approach to the study of a challenging set of sequences-the bacterial chemotaxis protein CheY, the N-terminal receiver domain of the nitrogen regulation protein NT-NtrC, and the sporulation response regulator Spo0F. These are all response regulators involved in signal transduction. Despite functional similarity and structural homology, they exhibit low sequence identity. PFM sequence comparison demonstrates a statistically significant qualitative difference between the sequence of CheY and those of the other two proteins that is not found using conventional alignment methods. This difference is shown to be consonant with structural characteristics, using distance matrix comparisons. We also demonstrate that residues participating strongly in native contacts during unfolding are distributed differently in CheY than in the other two proteins. The PFM result is also in accord with dynamic simulation results of several types. Molecular dynamics simulations of all three proteins were carried out at several temperatures, and it is shown that the dynamics of CheY are predicted to differ from those of NT-NtrC and Spo0F. The predicted dynamic properties of the three proteins are in good agreement with experimentally determined B factors and with fluctuations predicted by the Gaussian network model. We pinpoint the differences between the PFM and traditional sequence comparisons and discuss the informatic basis for the ability of the PFM approach to detect physical differences between these sequences that are not apparent from traditional alignment-based comparison.
authors.affiliation: Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853.
authors.forename: Yi
authors.initials: Y
authors.lastname: He
authors.affiliation: Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853.
authors.forename: Gia G
authors.initials: GG
authors.lastname: Maisuradze
authors.affiliation: Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853.
authors.forename: Yanping
authors.initials: Y
authors.lastname: Yin
authors.affiliation: Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853.
authors.forename: Khatuna
authors.initials: K
authors.lastname: Kachlishvili
authors.affiliation: Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853.|Department of Pharmacological Sciences, The Icahn School of Medicine at Mount Sinai, New York, NY 10029.
authors.forename: S
authors.initials: S
authors.lastname: Rackovsky
authors.affiliation: Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853; has5@cornell.edu.
authors.forename: Harold A
authors.initials: HA
authors.lastname: Scheraga
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D001665:Binding Sites / Q000235:genetics; D019295:Computational Biology / Q000379:methods; D000072236:Methyl-Accepting Chemotaxis Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008958:Models, Molecular; D000072417:Protein Domains; D016415:Sequence Alignment / Q000379:methods*; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins
keywords: all-atom simulations; amino acid physical properties; protein fluctuations