. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 194 N. SAPERAS ET AL BPTI 1 2345. R1 i R2 * R3 « R3 C W 12345 W 1 2 3 Figure 6. Determination of the number of cysteine residues according to the method of Creighton (1980). A. Standard of BPTI (Boehringer Mannheim); B. Rl from llydmlaxns colliei: C. R2 from H colliei. Reaction with lodacetamide (I); iodoacetamide/iodoacetate in ratios of l:l (2). 1:3 (3). and 1:9 (4); and with iodoacetate (5). W = whole basic protein pattern from //. colliei testis. protamines originated very probably from the same an- cestral DNA sequence
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 194 N. SAPERAS ET AL BPTI 1 2345. R1 i R2 * R3 « R3 C W 12345 W 1 2 3 Figure 6. Determination of the number of cysteine residues according to the method of Creighton (1980). A. Standard of BPTI (Boehringer Mannheim); B. Rl from llydmlaxns colliei: C. R2 from H colliei. Reaction with lodacetamide (I); iodoacetamide/iodoacetate in ratios of l:l (2). 1:3 (3). and 1:9 (4); and with iodoacetate (5). W = whole basic protein pattern from //. colliei testis. protamines originated very probably from the same an- cestral DNA sequence before the divergence of Chon- drichthyes and Osteichthyes during the Devonian period" (Chevaillier et ai. 1987). Second, there are very few iden- tities in the sequences of protamines Zl, Z2, and S4. Pos- sibly, these basic proteins have evolved neither from the same single ancestral polypeptide nor from the same gene family. Third, the intermediate basic proteins SI and S2 are not homologous to the sperm proteins. These data mean that the sperm (and spermiogenic) nuclear proteins from 5. canicula are coded by a series of genes that express coordinately during spermiogenesis but do not possess a close evolutionary relationship. The comparison of ratfish protamines with those from 5. canicula brings out yet a greater variability in this sys- tem of molecules. Ratfish R3 protamine differs greatly from S. canicula Z3 protamine (Table I). R3 contains a relatively great diversity of amino acid residues (14 dif- ferent types), contrasted with only five types of residues that constitute Z3. In addition, ratfish is relatively poor in arginine ( mol % versus mol % in dogfish), and its N-terminal sequence shows the presence of clusters of heterogeneous basic residues (RRRH, KKKRK) that are not present in Z3, nor in the protamines of bony fish. The minor protamine mt) presents compositional char- acteristics similar to R3 (Table I). The comparison between the amino acid co
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
