The Walker A binding motif has a lysine side chain, which is essential for the binding of ATP. The lysine residue forms hydrogen bonds with the oxygen atoms of two phosphate groups within ATP, therefore creating proximity and orientation of ATP in the binding site.
A specific amino acid sequence, known as the Walker A motif, enables the attachment of adenosine triphosphate (ATP) through a crucial lysine residue. This interaction involves hydrogen bonding between the lysine's side chain and phosphate groups in ATP, positioning it optimally for binding.