Molecular modeling of human red blood cell pyruvate kinase: Structural implications of a novel G-1091 to A mutation causing severe nonspherocytic hemolytic anemia. Blood 90: 4987–4995

We present a novel G1091 to A mutation in the human liver of RBC PK, whereas the G1529 to A mutation leads to the and red blood cell (RBC) pyruvate kinase (PK) gene causing substitution of a conserved arginine residue with glutamine severe hemolytic anemia. In two families, three children in the C-domain. Molecular modelling of human RBC PK, were severely PK-deficient compound heterozygotes exhib- based on the crystal structure of cat muscle PK, shows that iting the G1091 to A mutation and a common G1529 to A muta- both mutations are located outside the catalytic site at the tion on the other allele. In one family, the mother, a G1091 to interface of domains A and C. The mutations are likely to A heterozygote, later had a second baby with a new hus- disrupt the critical conformation of the interface by introduc-band, also a G1091 to A carrier. The baby was homozygous ing alternative salt bridges. In this way the Gly364 to Asp for the G1091 to A mutation and died 6 weeks after birth from and Arg510 to Gln substitutions may cause PK deficiency by severe hemolysis. Both mutant alleles were expressed at influencing the allosteric properties of the enzyme. the RNA level. The G1091 to A mutation results in the substitu- q 1997 by The American Society of Hematology. tion of a conserved glycine by an aspartate in domain A P on the crystal structure of muscle PK, shows that none ofthe mutations involves the catalytic site, but both are likelyYRUVATE KINASE (PK) catalyzes the conversion ofphosphoenol pyruvate to pyruvate and is an important regulator of glycolysis. Two different genes have been char- to disrupt the structure of the critical interface between do-mains A and C. We postulate that the G1091 to A and commonacterized in mammals. One encodes the liver and red bloo