| The tropical clam Lucina pectinata inhabits in the southwest coast of Puerto Rico and contains three types of hemoglobins, each characterized by distinct physico-chemical properties. Hemoglobin I (HbI) is a monomeric hemoglobin of 142 amino acid residues that serves as carder for H2S. The amino acid sequence of HbI was obtained by DNA sequencing of cDNAs prepared with RT-PCR and RACE methods. The cDNA-derived amino acid sequence of HbI shows nine differences when compared to the reported protein sequence by X-Ray Crystallography. The molecular weight calculated from the cDNA-derived amino acid sequence of HbI is in agreement with the molecular weight of 14,854 Daltons determined previously by Electrospray Ionization Mass Spectrometry. Northern Blot analysis revealed that the mRNAHbI is approximately 1.4 Kb long. The size of the HbI cDNA estimated from sequence analysis of overlapping clones was 1,321 bp for the full-length cDNA. Thus, the mRNAHbI size calculated from Northern Blot data agrees with the estimated size derived from cDNA cloning data. |
