Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Critical Care giúp cho các bạn có thêm kiến thức về ngành y học đề tài: The protamine family of sperm nuclear proteins. | Protein family review The protamine family of sperm nuclear proteins Rod Balhorn Address Biosciences and BioTechnology Division Chemistry Materials and Life Sciences Lawrence Livermore National Laboratory East Avenue Livermore CA 94550 USA. Email balhorn2@ Published 26 September 2007 Genome Biology 2007 8 227 doi gb-2007-8-9-227 The electronic version of this article is the complete one and can be found online at http 2007 8 9 227 2007 BioMed Central Ltd Summary The protamines are a diverse family of small arginine-rich proteins that are synthesized in the late-stage spermatids of many animals and plants and bind to DNA condensing the spermatid genome into a genetically inactive state. Vertebrates have from one to 15 protamine genes per haploid genome which are clustered together on the same chromosome. Comparison of protamine gene and amino-acid sequences suggests that the family evolved from specialized histones through protamine-like proteins to the true protamines. Structural elements present in all true protamines are a series of arginine-rich DNA-anchoring domains often containing a mixture of arginine and lysine residues in non-mammalian protamines and multiple phosphorylation sites. The two protamines found in mammals P1 and P2 are the most widely studied. P1 packages sperm DNA in all mammals whereas protamine P2 is present only in the sperm of primates many rodents and a subset of other placental mammals. P2 but not P1 is synthesized as a precursor that undergoes proteolytic processing after binding to DNA and also binds a zinc atom the function of which is not known. P1 and P2 are phosphorylated soon after their synthesis but after binding to DNA most of the phosphate groups are removed and cysteine residues are oxidized forming disulfide bridges that link the protamines together. Both P1 and P2 have been shown to be required for normal sperm function in primates and many rodents. Gene organization and evolutionary .
