Conformation of polypyrimidine tract binding protein in solution.
The polypyrimidine tract binding protein (PTB) is an RNA binding protein that normally functions as a regulator of alternative splicing but can also be recruited to stimulate translation initiation by certain picornaviruses. High-resolution structures of the four RNA recognition motifs (RRMs) that make up PTB have previously been determined by NMR. Here, we have used small-angle X-ray scattering to determine the low-resolution structure of the entire protein. Scattering patterns from full-length PTB and deletion mutants containing all possible sequential combinations of the RRMs were collected. All constructs were found to be monomeric in solution. Ab initio analysis and rigid-body modeling utilizing the high-resolution models of the RRMs yielded a consistent low-resolution model of the spatial organization of domains in PTB. Domains 3 and 4 were found to be in close contact, whereas domains 2 and especially 1 had loose contacts with the rest of the protein.
Petoukhov
Maxim V
MV
European Molecular Biology Laboratory, Hamburg Outstation, Notkestrasse 85, 22603 Hamburg, Germany.
Monie
Tom P
TP
Allain
Frédéric H-T
FH
Matthews
Stephen
S
Curry
Stephen
S
Svergun
Dmitri I
DI
D006801:Humans; D008958:Models, Molecular; D038941:Polypyrimidine Tract-Binding Protein / Q000737:chemistry* / Q000235:genetics; D011487:Protein Conformation; D017434:Protein Structure, Tertiary / Q000235:genetics; D017384:Sequence Deletion; D012996:Solutions; D014961:X-Ray Diffraction
D012996:Solutions; D038941:Polypyrimidine Tract-Binding Protein