Residual occurrence and energy property of proteins in HNP model

(整期优先)网络出版时间:2015-11-21
/ 1
Fourcategoriesofglobularproteins,includingall-α,all-β,α+β,andα/βtypes,aresimplifiedastheoff-latticeHNPmodelinvolvingthesecondary-structuralinformationofeachprotein.Thepropensityofthreetypesofresidues,i.e.,H,N,andPtoformasecondarystructureisinvestigatedbasedon146proteinsamples.WefindthatPresiduesareeasytoformα-helices,whereasHresidueshaveahighertendencytoconstructβ-sheets.ThestatisticalanalysisalsoindicatesthattheoccurrenceofPresiduesisinvariablyhigherthanthatofHresidues,whichisindependentofproteincategory.Changesinbond-andnon-bondedpotentialenergiesofallproteinsamplesunderawidetemperaturerangearepresentedbycoarse-grainedmoleculardynamics(MD)simulation.Thesimulationresultsclearlyshowalinearrelationshipbetweenthebond-stretching/bendingpotentialenergyandthereducedtemperature.Thebond-torsionalandnon-bondedpotentialenergiesshowdistincttransitionswithtemperature.Thebond-torsionalenergyincreasestothemaximumandthendecreaseswiththeincreaseoftemperature,whichisoppositetothechangeinnon-bondedpotentialenergy.Thetransitiontemperatureofnon-bondedpotentialenergyisindependentoftheproteincategory,whilethatofbond-torsionalenergyiscloselyrelatedtotheproteinsecondarystructure,i.e.,α-helixorβ-sheet.Thequantitativelybonded-andsemiquantitativelynon-bondedpotentialenergyof24α+βand23α/βproteinsamplesaresuccessfullypredictedaccordingtothestatisticalresultsobtainedfromMDsimulations.