1IYC

Solution structure of antifungal peptide, scarabaecin

Summary for 1IYC

• Entry DOI: 10.2210/pdb1iyc/pdb
• NMR Information: BMRB: 5491
• Descriptor: scarabaecin (1 entity in total)
• Functional Keywords: antifungal peptide, antimicrobial peptide, beetle, chitin-binding, antifungal protein
• Cellular location: Secreted: Q86SC0
• Total number of polymer chains: 1
• Total formula weight: 4087.74

Authors

Hemmi, H.,Ishibashi, J.,Tomie, T.,Yamakawa, M. (deposition date: 2002-08-05, release date: 2003-06-24, Last modification date: 2024-11-13)

Primary citation

Hemmi, H.,Ishibashi, J.,Tomie, T.,Yamakawa, M.
Structural Basis for New Pattern of Conserved Amino Acid Residues Related to Chitin-binding in the Antifungal Peptide from the Coconut Rhinoceros Beetle Oryctes rhinoceros
J.BIOL.CHEM., 278:22820-22827, 2003

PubMed Abstract: Scarabaecin isolated from hemolymph of the coconut rhinoceros beetle Oryctes rhinoceros is a 36-residue polypeptide that has antifungal activity. The solution structure of scarabaecin has been determined from twodimensional 1H NMR spectroscopic data and hybrid distance geometry-simulated annealing protocol calculation. Based on 492 interproton and 10 hydrogen-bonding distance restraints and 36 dihedral angle restraints, we obtained 20 structures. The average backbone root-mean-square deviation for residues 4-35 is 0.728 +/- 0.217 A from the mean structure. The solution structure consists of a two-stranded antiparallel beta-sheet connected by a type-I beta-turn after a short helical turn. All secondary structures and a conserved disulfide bond are located in the C-terminal half of the peptide, residues 18-36. Overall folding is stabilized by a combination of a disulfide bond, seven hydrogen bonds, and numerous hydrophobic interactions. The structural motif of the C-terminal half shares a significant tertiary structural similarity with chitin-binding domains of plant and invertebrate chitin-binding proteins, even though scarabaecin has no overall sequence similarity to other peptide/polypeptides including chitin-binding proteins. The length of its primary structure, the number of disulfide bonds, and the pattern of conserved functional residues binding to chitin in scarabaecin differ from those of chitin-binding proteins in other invertebrates and plants, suggesting that scarabaecin does not share a common ancestor with them. These results are thought to provide further strong experimental evidence to the hypothesis that chitin-binding proteins of invertebrates and plants are correlated by a convergent evolution process.

PubMed: 12676931
DOI: 10.1074/jbc.M301025200

Experimental method

SOLUTION NMR