Characterization of Two Forms of Mouse Salivary Androgen-Binding Protein (ABP): Implications for Evolutionary Relationships and Ligand-Binding Function
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- 作者：Robert C. Karn and Christina M. Laukaitis
- 刊名：Biochemistry
- 出版年：2003
- 出版时间：June 17, 2003
- 年：2003
- 卷：42
- 期：23
- 页码：7162 - 7170
- 全文大小：294K
- 年卷期：v.42,no.23(June 17, 2003)
- ISSN：1520-4995
文摘
Mouse salivary androgen-binding protein (ABP) is a member of the secretoglobin familyproduced in the submaxillary glands of house mice (Mus musculus). We report the cDNA sequences andamino acid sequences of the 
mages/gifchars/beta2.gif" BORDER=0 ALIGN="middle"> and mages/gifchars/gamma.gif" BORDER=0 > subunits of ABP from a mouse cDNA library, identifying the twosubunits by their pIs and molecular weights. An anomalously high molecular weight of the mages/gifchars/alpha.gif" BORDER=0> subunit islikely due to glycosylation at a single site. A phylogenetic comparison of the three subunits of ABP withthe chains of other mammalian secretoglobins shows that ABP is most closely related to mouse lachrymalprotein and to the major cat allergen Fel dI. An evaluation of the most conserved residues in ABP and theother secretoglobins, in light of structural data reported by others [Callebaut, I., Poupon, A., Bally, R.,Demaret, J.-P., Housset, D., Delettre, J., Hossenlopp, P., and Mornon, J.-P. (2000) Ann. N.Y. Acad. Sci.923, 90-112; Pattabiraman, N., Matthews, J., Ward, K., Mantile-Selvaggi, G., Miele, L., and Mukherjee,A. (2000) Ann. N.Y. Acad. Sci. 923, 113-127], allows us to draw conclusions about the critical residuesimportant in ligand binding by the two different ABP dimers and to assess the importance of ligandbinding in the function of the molecule. In addition to the cDNAs, which represent those of the musculussubspecies of Mus musculus, we also report the coding regions of the mages/gifchars/beta2.gif" BORDER=0 ALIGN="middle"> and mages/gifchars/gamma.gif" BORDER=0 > subunit cDNAs from twoother mouse inbred strains which represent the other two subspecies: M. musculus domesticus and M.musculus castaneus. The high nonsynonymous/synonymous substitution rate ratios (Ka/Ks) for both the mages/gifchars/beta2.gif" BORDER=0 ALIGN="middle">and mages/gifchars/gamma.gif" BORDER=0 > subunits suggest that these two proteins are evolving under strong directional selection, as has beenreported for the mages/gifchars/alpha.gif" BORDER=0> subunit [Hwang, J., Hofstetter, J., Bonhomme, F., and Karn, R. (1997) J. Hered. 88,93-97; Karn, R., and Clements, M. (1999) Biochem. Genet. 37, 187-199].