However, nucleotide binding
to the mutated histidine transport complex in membrane
vesicles [81] and ATPase activity of the puri-
¢ed variant of MalK [83] were largely unaltered.
Thus, the residues might be crucial for a subsequent
step. E¤cient nucleotide-binding activity was also
shown for another variant of HisP carrying a mutation
of the moderately conserved threonine residue
(T205) within the same region [81].