2b72
|
T4 Lysozyme mutant L99A at 100 MPa
OverviewOverview
Formation of a water-expelling nonpolar core is the paradigm of protein, folding and stability. Although experiment largely confirms this picture, water buried in "hydrophobic" cavities is required for the function of, some proteins. Hydration of the protein core has also been suggested as, the mechanism of pressure-induced unfolding. We therefore are led to ask, whether even the most nonpolar protein core is truly hydrophobic (i.e., water-repelling). To answer this question we probed the hydration of an, approximately 160-A(3), highly hydrophobic cavity created by mutation in, T4 lysozyme by using high-pressure crystallography and molecular dynamics, simulation. We show that application of modest pressure causes, approximately four water molecules to enter the cavity while the protein, itself remains essentially unchanged. The highly cooperative filling is, primarily due to a small change in bulk water activity, which implies that, changing solvent conditions or, equivalently, cavity polarity can, dramatically affect interior hydration of proteins and thereby influence, both protein activity and folding.
About this StructureAbout this Structure
2B72 is a Single protein structure of sequence from Bacteriophage t4 with CL and BME as ligands. Active as Lysozyme, with EC number 3.2.1.17 Full crystallographic information is available from OCA.
ReferenceReference
Cooperative water filling of a nonpolar protein cavity observed by high-pressure crystallography and simulation., Collins MD, Hummer G, Quillin ML, Matthews BW, Gruner SM, Proc Natl Acad Sci U S A. 2005 Nov 15;102(46):16668-71. Epub 2005 Nov 3. PMID:16269539
Page seeded by OCA on Wed Nov 21 08:36:37 2007