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Primary structures of M6 and M7 of mugiline beta (Mugil japonicus)
Abstract:
Mugiline beta isolated from mature sperm nuclei of the Formosan grey mullet, belonging to Perciformes, was fractionated into seven components (M1-M7), by chromatography on CM-Sephadex C-25. The amino acid sequences of the two major components (M6 and M7) were then determined. M6 contained 33 amino acid residues per molecule: Arg, 21; Thr, 1; Ser, 1; Glu, 1; Pro, 3; Ala, 2; Val, 2; Met, 0.3 and Ile, 1.7. The amino acid sequence of M6 is: Pro-Arg-Arg-Arg-Arg-Glu-Thr-Ser-Arg-Pro-Ile-Arg-Arg-Arg-Arg-Arg-Ala-Pro- Ile (Met)-Arg-Arg-Arg-Arg-Arg-Val-Val-Arg-Arg-Arg-Arg. Isoleucine at position 22 is partially replaced by methionine. M7 had an amino acid sequence similar to that of M6 except that glutamic acid at position 6 of M6 was replaced by glutamine. A high degree of homology in the sequences was found between mugiline beta from mullet and thynnine from tuna fish, which also belongs to Perciformes.
Insights
Mugiline beta, a protein from grey mullet sperm, was analyzed, revealing two main components (M6 and M7) with distinct amino acid sequences. These sequences showed homology with tuna proteins, suggesting evolutionary links within Perciformes fish.
Area of Science:
- Biochemistry
- Molecular Biology
- Marine Biology
Background:
- Mugiline beta is a protein found in the sperm nuclei of the Formosan grey mullet (Mugil cephalus).
- Perciformes fish, including mullets and tuna, represent a diverse and evolutionarily significant group.
Purpose of the Study:
- To isolate and characterize mugiline beta from grey mullet sperm.
- To determine the amino acid sequences of the major mugiline beta components.
- To investigate the sequence homology between mugiline beta and other fish proteins.
Main Methods:
- Fractionation of mugiline beta using chromatography on CM-Sephadex C-25.
- Determination of amino acid sequences for the M6 and M7 components.
- Comparative sequence analysis with thynnine from tuna fish.
Main Results:
- Mugiline beta was fractionated into seven components (M1-M7).
- The amino acid sequences of M6 (33 residues) and M7 were determined, with M7 differing from M6 by a single glutamine substitution.
- Significant sequence homology was observed between mugiline beta and thynnine, both belonging to the Perciformes order.
Conclusions:
- The study successfully characterized two major components of mugiline beta from grey mullet sperm.
- The determined amino acid sequences provide insights into the protein's structure and function.
- Observed homology suggests conserved evolutionary pathways for these proteins within Perciformes fish.