At. Alexandrescu et al., A FRAGMENT OF STAPHYLOCOCCAL NUCLEASE WITH AN OB-FOLD STRUCTURE SHOWSHYDROGEN-EXCHANGE PROTECTION FACTORS IN THE RANGE REPORTED FOR MOLTENGLOBULES, Protein science, 5(9), 1996, pp. 1942-1946
Hydrogen-exchange rates for an OB-fold subdomain fragment of staphyloc
occal nuclease have been measured at pH 4.7 and 4 degrees C, condition
s close to the minimum of acid/base catalyzed exchange. The strongest
protection from solvent exchange is observed for residues from a five-
stranded beta-barrel in the NMR structure of the protein. Protection f
actors, calculated from the experimental hydrogen-exchange rates, rang
e between 1 and 190. Similarly small protection factors have in many c
ases been attributed to ''molten globule'' conformations that are supp
osed to lack a specific tertiary structure. The present results sugges
t that marginal protection from solvent exchange does not exclude well
-defined structure.