Hb Watts [alpha 74(EF3) or alpha 75(EF4)Asp-->0]: a shortened alpha chain variant due to the deletion of three nucleotides in exon 2 of the alpha 2-globin gene.
We have identified a new, slightly unstable alpha chain hemoglobin variant, present in a Mexican-American family. Amino acid sequencing and mass spectral analysis of the aberrant peptide (alpha T-9) of the variant revealed that the aspartic acid is deleted either at position 74 or 75 of one of the alpha-globin chains. Sequencing of the amplified alpha 2- or alpha 1-globin genes revealed a trinucleotide deletion (GAC) at codon 74 or 74 of the alpha 2 gene. Although the aspartic acid residues of 74 and 75 of the alpha chain are neither a heme nor an inter chain contact, the slight instability of Hb Watts may be due to disturbance of the central cavity of hemoglobin by the deletion of an aspartic acid residue in the EF helix. Hb Watts is the first example of a trinucleotide deletion in the alpha 2-globin gene.
Rahbar
S
S
Hemoglobin Research Laboratory, City of Hope National Medical Center, Duarte, CA 91010-0269, USA.
Lee
C
C
Fáirbanks
V F
VF
McCormick
D J
DJ
Kubik
K
K
Madden
B J
BJ
Nozari
G
G
D000328:Adult; D000595:Amino Acid Sequence; D005091:Exons / Q000235:genetics; D015673:Fatigue Syndrome, Chronic / Q000235:genetics*; D005260:Female; D017353:Gene Deletion; D005914:Globins / Q000235:genetics; D006455:Hemoglobins, Abnormal / Q000235:genetics*; D006801:Humans; D017058:Mexican Americans; D008969:Molecular Sequence Data
D006455:Hemoglobins, Abnormal; C108106:hemoglobin Watts; D005914:Globins