Hb S-São Paulo: A new sickling hemoglobin with stable polymers and decreased oxygen affinity

Hb S-São Paulo (SP) [HBB:c.20A > T p.Glu6Val; c.196A > G p.Lys65Glu] is a new double-mutant hemoglobin that was found in heterozygosis in an 18-month-old Brazilian male with moderate anemia. It behaves like Hb S in acid electrophoresis, isoelectric focusing and solubility testing but shows different behavior in alkaline electrophoresis, cation-exchange HPLC and RP-HPLC. The variant is slightly unstable, showed reduced oxygen affinity and also appeared to form polymers more stable than the Hb S. Molecular dynamics simulation suggests that the polymerization is favored by interfacial electrostatic interactions. This provides a plausible explanation for some of the reported experimental observations Fil: Jorge, Susan E. D. C.. Universidade Estadual de Campinas; Brasil Fil: Petruk, Ariel Alcides. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentina Fil: Kimura, Elza M.. Universidade Estadual de Campinas; Brasil Fil: Oliveira, Denise M.. Universidade Estadual de Campinas; Brasil Fil: Caire, Lucas. Universidade Estadual de Campinas; Brasil Fil: Suemasu, Cintia N.. Universidade Estadual de Campinas; Brasil Fil: Silveira, Paulo A. A.. Albert Einstein Institute; Brasil Fil: Albuquerque, Dulcineia M.. Universidade Estadual de Campinas; Brasil Fil: Costa, Fernando F.. Universidade Estadual de Campinas; Brasil Fil: Skaf, Munir S.. Universidade Estadual de Campinas; Brasil Fil: Martínez, Leandro. Universidade de Sao Paulo; Brasil Fil: De Fatima Sonati, Maria. Universidade Estadual de Campinas; Brasil