7DTL

Crystal structure of PSK, an antimicrobial peptide from Chrysomya megacephala

Summary for 7DTL

• Entry DOI: 10.2210/pdb7dtl/pdb
• Descriptor: PSK (2 entities in total)
• Functional Keywords: antimicrobial peptide, mitochondrial atpase inhibitor, psk, antimicrobial protein
• Biological source: Chrysomya megacephala
• Total number of polymer chains: 2
• Total formula weight: 20823.05

Authors

Xiao, C.,Xiao, Z.,Wang, S.,Liu, W. (deposition date: 2021-01-05, release date: 2021-07-14, Last modification date: 2024-03-27)

Primary citation

Xiao, C.,Xiao, Z.,Hu, C.,Lu, J.,Cui, L.,Zhang, Y.,Dai, Y.,Zhang, Q.,Wang, S.,Liu, W.
Crystal and solution structures of a novel antimicrobial peptide from Chrysomya megacephala.
Acta Crystallogr D Struct Biol, 77:894-903, 2021

PubMed Abstract: Antimicrobial peptides (AMPs) are small amphipathic peptides that exhibit bactericidal activity against a wide range of pathogenic microorganisms and are considered to be potential substitutes for antibiotics effective against microbial infection. PSK, an 84-amino-acid AMP recently isolated from Chrysomya megacephala larvae, probably belongs to the mitochondrial ATPase inhibitor family according to its sequence. No member of this family from an insect has been structurally characterized to date. In this study, the crystal structure of full-length PSK determined by molecular replacement using an ab initio modeled ensemble as a search model and a solution structure obtained from small-angle X-ray scattering (SAXS) measurements are reported. The crystal structure reveals a distinct fold compared with those of homologous peptides, in that PSK comprises two antiparallel α-helices rather than a single long helix, which is in good agreement with the SAXS-based ab initio model. However, the peptide exists as a monomer in solution, even though a stable dimer was observed in the crystal structure. This apparent contradiction may reflect different oligomerization states that may be implicated in its bioactivity. The data presented here have established a solid basis for further mechanistic studies of this novel insect AMP.

PubMed: 34196616
DOI: 10.1107/S2059798321004629

Experimental method

X-RAY DIFFRACTION (1.8 Å)