ausblenden:
Schlagwörter:
red cell membrane; band 3 protein; anion transport; 2DIDS
4,4'-diisothiocyanato dihydrostilbene-2,2'-disulfonic acid
Zusammenfassung:
The time course of intramolecular crosslinking by H2DIDS of two lysine residues called lys a and lys b on the chymotryptic 60k and 35k dalton segments, respectively, of the band 3 protein is described. One of the two isothiocyanate groups of the H2DIDS molecule may react first either with lys a or lys b. In a subsequent step the crosslink is established by a reaction of the other isothiocyanate group with lys b or lys a, respectively. The mathematical analysis of the data shows that the reaction rate with lys a is 2 to 3.5 times higher than the reaction rate with lys b. The establishment of the crosslink by H2DIDS molecules that are unilaterally bound to either lys a or lys b takes place at a rate that is about one order of magnitude lower than the rate of establishment of the unilateral bond. A more detailed analysis of the data suggests that the H2DIDS binding site may exist in two different conformational states in which lys a is either more susceptible or less susceptible to covalent bond formation with H2DIDS.
