primary structure
noun
1
- Biochemistry the characteristic sequence of amino acids forming a protein or polypeptide chain, considered as the most basic element of its structure【生化】（氨基酸）一级结构, 初生结构, 原结构。
2
- Aeronautics the parts of an aircraft whose failure would seriously endanger safety【航空】主要结构; 承力骨架。