COMPLETE AMINO-ACID SEQUENCE OF RABBIT BETA-2-MICROGLOBULIN

The complete amino acid sequence of rabbit β2-microglobulin has been determined as follows: Val-Gln-Arg-Aia-Pro-Asn-Val-Gln-Val-Tyr-Ser-Arg-His-Pro-Ala-Glu-Asn-Gly-Lys-Pro-Asn-Phe-Leu-Asn-Cys-Tyr-Val-Ser-Gly-Phe-His-Pro-Pro-Gln-Ile-Asp-Ile-Glu-Leu-Leu-Lys-Asn-Gly-Val-Lys-Ile-Glu-Asn-Val-Glu-Gln-Ser-Asp-Leu-Ser-Phe-Asn-Lys-Asp-Trp-Ser-Phe-Tyr-Leu-Leu-Val-His-Thr-Glu-Phe-Thr-Pro-Asn-Asn-Lys-Asn-Glu-Tyr-Ser-Cys-Arg-Val-Lys-His-Val-Thr-Leu-Lys-Glu-Pro-Met-Thr-Val-Lys-Trp-Asp-Arg-Asp-Tyr. Comparison of this sequence to that reported from human β2-microglobulin [Cunningham, B. A., Wang, J. L., Bergg&rd, I., & Peterson, P. A. (1973) Biochemistry 12, 4811] shows a homology of 71%, with a minimum 13% difference in the nucleotide sequences of the genes encoding the two proteins. A single insertion must be introduced before position 68 of the rabbit protein in order to maintain maximum homology to human β2-microglobulin. Amino acid substitutions which can be attributed to single base changes are evenly distributed throughout the molecule, whereas the majority of those requiring multiple base changes are restricted to the carboxy-terminal third of the molecule. Although the rabbit β2-microglobulin analyzed in this study was isolated from the pooled urine of 15 rabbits, no heterogeneity in amino acid sequence was observed. © 1979, American Chemical Society. All rights reserved.