Proline codon 30 (CCT) in exon 3 was changed to alanine (GCT) (p.P30A) and a loxP site flanked neomycin resistance gene cassette was inserted into intron 2. The neo cassette was removed through subsequent Cre-mediated recombination. The affected residue is located in loop 1, between helix 1 and 2, of the encoded peptide and is thought to be involved in oxygenated alpha-globin binding. (J:338784)