NR ATDS
AU Molloy,D.P.; Chen,B.
TI Predicted consequences of site-directed mutagenesis and the impact of species variation on prion protein misfolding through the N-terminal domain
QU Journal of Molecular Modeling 2005 Nov; 11(6): 468-73
PT journal article; research support, non-u.s. gov't
AB Variant Creutzfeldt-Jakob disease (vCJD) is considered to afflict humans through the acquisition of variant isomers and misfolding of the normal cellular prion polypeptide, PrPc. Although the exact mechanism of the misfolding is not been yet clearly understood, this paper provides four additional pieces of evidence in support of the hypothesis that misfolding within PrPc involves N-terminal residues, up to and including Asn178. Structural predictions for N-terminal residues between Leu4 and Gly124 revealed that Leu4-Leu19 might adopt a helical conformation. Furthermore, measurement of C(alpha) distance variations, as determined from available NMR solution structures of wild type, as well as the biologically significant Val166, Asn170 and Lys220 variants of PrPc, revealed previously unreported global and local conformational differences may occur in PrPc as a result of these amino-acid substitutions. Notably, three regions, His140-Tyr150 and Met166-Phe175 showed deviations greater than 3 A in their C(alpha)-coordinates (cf wild type) indicating that the majority of the N-terminal domain is likely to contribute to the misfolding of PrPc. Minor variations in the orientation of amino acids Thr193-Glu200, located towards the C terminus of the protein, were also noted. This most likely indicates the presence of a hinge mechanism, inherent to a Helix-Loop-helix (HLH) motif formed by amino acids within alpha2, LIII and alpha3, in order to accommodate reorientation of the motif in response to misalignment of the N-terminal domain. An unexpected 3 angstroms deviation from the coordinates of the wild type polypeptide, absent from either Val166, Asn170 variants was observed over the region Arg154-Tyr155 within the Val166 form of PrPc. This may contribute to the explanation as to why patients carrying the Val166 isoform of PrPc may be more susceptible to vCJD.
IN Die Autoren meinen, mit strukturellen Konsequenzen einer Val(166)-Variante des Prionproteins eine mir bisher noch gar nicht bekannte besondere Empfänglichkeit von Trägern dieser Mutation für die neue Variante der Creutzfeldt-Jakob-Krankheit erklären zu können.
MH Amino Acid Sequence; Humans; Models, Molecular; Molecular Sequence Data; Mutagenesis, Site-Directed; PrPc Proteins/*chemistry/genetics/*metabolism; Protein Folding; Protein Structure, Secondary; Protein Structure, Tertiary
AD Research Office, Thames Valley University, Ealing, London, W5 2BS, UK. David.Molloy@tvu.ac.uk
SP englisch
PO Deutschland