... molecule takes the position of the adenine ring of ATP. The carbon and oxygen atoms of pantoate are shown inyellow and red, respectively. The carbon and oxygen atoms of ATP are shown in red, the nitrogen ... nPS, and in the case of His37, the v1torsion angle changes from 63.34° to)67.80° and )52.11° for the A-chain and B-chain of nPS, respectively. The imidazole ring of His34 pointsinwards in the ... Superimposition of the A-chain of nPS (green), the B-chain of nPS (cyan), and the substrate-free protein (1IHO.pdb; magenta). The carbon and oxygen atoms of pantoate are shown in green and red, respectively....