Cooperativity and specificity of association of a designed transmembrane peptide.
Thermodynamics studies aimed at quantitatively characterizing free energy effects of amino acid substitutions are not restricted to two state systems, but do require knowing the number of states involved in the equilibrium under consideration. Using analytical ultracentrifugation and NMR methods, we show here that a membrane-soluble peptide, MS1, designed by modifying the sequence of the water-soluble coiled-coil GCN4-P1, exhibits a reversible monomer-dimer-trimer association in detergent micelles with a greater degree of cooperativity in C14-betaine than in dodecyl phosphocholine detergents.
Gratkowski
Holly
H
The Johnson Research foundation, Department of Biochemistry and University of Pennsylvania, Philadelphia PA 19104-6059, USA.
Dai
Qing-Hong
QH
Wand
A Joshua
AJ
DeGrado
William F
WF
Lear
James D
JD
D000595:Amino Acid Sequence; D001622:Betaine / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism*; D003902:Detergents / Q000494:pharmacology; D019281:Dimerization; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D008969:Molecular Sequence Data; D010452:Peptide Biosynthesis; D010455:Peptides / Q000737:chemistry*; D010767:Phosphorylcholine / Q000031:analogs & derivatives* / Q000494:pharmacology; D013816:Thermodynamics; D014461:Ultracentrifugation
D003902:Detergents; D008823:Micelles; D010455:Peptides; D010767:Phosphorylcholine; D001622:Betaine; C028810:dodecylphosphocholine