Synthetic human prion protein octapeptide repeat binds to the proteinase K active site.
Proteinase K is widely used in tests for the presence of infectious prion protein causing fatal spongiform encephalopathies. To investigate possible interactions between the enzyme and the functionally important N-terminal prion domain, we crystallized mercury-inhibited proteinase K in the presence of the synthetic peptides GGGWGQPH and HGGGW. The octapeptide sequence is identical to that of a single octapeptide repeat (OPR) from the physiologically important OPR region. Here, we present the first direct evidence for the complex formation between a proteolytic enzyme and a segment of human prion molecule. The X-ray structures of the complexes at 1.4 and 1.8A resolution, respectively, revealed that in both cases the segment GGG is strongly bound as a real substrate at the substrate recognition site of the proteinase forming an antiparallel beta-strand between the two parallel strands of Asn99-Tyr104 and Ser132-Gly136. The complex is stabilized through an extended H-bonding network.
Georgieva
Dessislava
D
Zentrum für Experimentelle Medizin, Institut für Biochemie und Molekularbiologie I, Universitätsklinikum Hamburg-Eppendorf, c/o DESY, Notkestrasse 85, Geb. 22a, 22603 Hamburg, Germany.
Rypniewski
Wojciech
W
Echner
Hartmut
H
Perbandt
Markus
M
Koker
Mirjam
M
Clos
Joachim
J
Redecke
Lars
L
Bredehorst
Reinhard
R
Voelter
Wolfgang
W
Genov
Nicolay
N
Betzel
Christian
C
D001665:Binding Sites; D003198:Computer Simulation; D018360:Crystallography, X-Ray / Q000379:methods*; D019281:Dimerization; D019286:Endopeptidase K / Q000737:chemistry*; D004789:Enzyme Activation; D006801:Humans; D008956:Models, Chemical; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry; D010455:Peptides / Q000737:chemistry*; D011328:Prions / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
D046912:Multiprotein Complexes; D010455:Peptides; D011328:Prions; D019286:Endopeptidase K