Proposed molten globule intermediates in fd phage penetration and assembly.
The fd filamentous phage can be contracted to short rods called I-forms and to spheroidal particles called S-forms. The conversions from fd----I-forms----S-forms were previously suggested to mimic steps in fd penetration. The same conversions, in reverse order, were suggested to mimic steps in fd assembly. The I-forms and S-forms bind the hydrophobic probe, 1-anilino-napthalene-8-sulfonate (ANS); under the same conditions, fd binds this probe very poorly. Rigidly packed side chains in fd and nonrigidly packed side chains in I-forms and S-forms would explain the differences in ANS binding. A compilation of the properties of I-forms and S-forms indicate that: (i) they have compact structures; (ii) they have secondary structures of the same type as native phage; (iii) they have non-native morphologies; and (iv) they may have nonrigid side chain packing. These are the properties of molten globules.
Dunker
A K
AK
Department of Biochemistry and Biophysics, Washington State University, Pullman 99164.
Ensign
L D
LD
Arnold
G E
GE
Roberts
L M
LM
D000817:Anilino Naphthalenesulfonates / Q000737:chemistry; D001435:Bacteriophages / Q000502:physiology* / Q000648:ultrastructure; D002213:Capsid / Q000737:chemistry; D008854:Microscopy, Electron; D011487:Protein Conformation
D000817:Anilino Naphthalenesulfonates; C027132:1-anilino-8-naphthalenesulfonate