4E86

Crystal structure of human alpha-defensin 5, HD5 (Leu29Aba mutant)

4E86 の概要

• エントリーDOI: 10.2210/pdb4e86/pdb
• 関連するPDBエントリー: 1ZMP 4E82 4E83
• 分子名称: Defensin-5, CHLORIDE ION (3 entities in total)
• 機能のキーワード: mutant leu29aba, beta-sheet, antimicrobial peptide, paneth cells, antimicrobial protein
• 由来する生物種: Homo sapiens (human)
• 細胞内の位置: Secreted: Q01523
• タンパク質・核酸の鎖数: 9
• 化学式量合計: 32201.93

構造登録者

Wu, X.,Pazgier, M. (登録日: 2012-03-19, 公開日: 2012-05-16, 最終更新日: 2023-12-06)

主引用文献

Rajabi, M.,Ericksen, B.,Wu, X.,de Leeuw, E.,Zhao, L.,Pazgier, M.,Lu, W.
Functional determinants of human enteric {alpha}-defensin HD5: crucial role for hydrophobicity at dimer interface.
J.Biol.Chem., 287:21615-21627, 2012

PubMed Abstract: Human α-defensins are cationic peptides that self-associate into dimers and higher-order oligomers. They bind protein toxins, such as anthrax lethal factor (LF), and kill bacteria, including Escherichia coli and Staphylococcus aureus, among other functions. There are six members of the human α-defensin family: four human neutrophil peptides, including HNP1, and two enteric human defensins, including HD5. We subjected HD5 to comprehensive alanine scanning mutagenesis. We then assayed LF binding by surface plasmon resonance, LF activity by enzyme kinetic inhibition, and antibacterial activity by the virtual colony count assay. Most mutations could be tolerated, resulting in activity comparable with that of wild type HD5. However, the L29A mutation decimated LF binding and bactericidal activity against Escherichia coli and Staphylococcus aureus. A series of unnatural aliphatic and aromatic substitutions at position 29, including aminobutyric acid (Abu) and norleucine (Nle) correlated hydrophobicity with HD5 function. The crystal structure of L29Abu-HD5 depicted decreased hydrophobic contacts at the dimer interface, whereas the Nle-29-HD5 crystal structure depicted a novel mode of dimerization with parallel β strands. The effect of mutating Leu(29) is similar to that of a C-terminal hydrophobic residue of HNP1, Trp(26). In addition, in order to further clarify the role of dimerization in HD5 function, an obligate monomer was generated by N-methylation of the Glu(21) residue, decreasing LF binding and antibacterial activity against S. aureus. These results further characterize the dimer interface of the α-defensins, revealing a crucial role of hydrophobicity-mediated dimerization.

PubMed: 22573326
DOI: 10.1074/jbc.M112.367995

実験手法

X-RAY DIFFRACTION (2.75 Å)