There Are Almost 500 Naturally Occurring Variants Of Hemoglobin Most Are The Result Of A Single Amino Acid Substitution 1 (25.33 KiB) Viewed 26 times
There Are Almost 500 Naturally Occurring Variants Of Hemoglobin Most Are The Result Of A Single Amino Acid Substitution 2 (22.23 KiB) Viewed 26 times
There are almost 500 naturally occurring variants of hemoglobin. Most are the result of a single amino acid substitution in a globin polypeptide chain. Some variants produce clinical illness, though not all variants have deleterious effects. A brief sample of hemoglobin variants is given. HbS (sickle cell Hb): substitutes a Val for a Glu on the surface Hb Cowtown: eliminates an ion pair involved in T-state stabilization Hb Memphis: substitutes one uncharged polar residue for another of similar size on the surface Hb Bibba: substitutes a Pro for a Leu involved in an a helix Hb Milwaukee: substitutes a Glu for a Val Hb Providence: substitutes an Asn for a Lys that normally projects into the central cavity of the tetramer Hb Philly: substitutes a Phe for a Tyr, disrupting hydrogen bonding at the a, ß, interface
Select the hemoglobin variant(s) that are described by each statement. (a) The variant least likely to cause pathological symptoms. (b) The variant(s) likely to show pl values different from that of HbA on an isoelectric focusing gel. (c) The variant most likely to show a decrease in BPG binding and an increase in the overall affinity of the hemoglobin for oxygen. Answer Bank Hb Philly Hb Providence Hb Cowtown Hb Bibba Hb Memphis Hbs Hb Milwaukee
Join a community of subject matter experts. Register for FREE to view solutions, replies, and use search function. Request answer by replying!