3e7r
X-ray Crystal Structure of Racemic Plectasin
Structural highlights
FunctionDEFPL_PSENR Antimicrobial peptide that potently acts against several species of Gram-positive bacteria (PubMed:16222292, PubMed:19472324). It selectively inhibits peptidoglycan biosynthesis through complex formation with the cell wall precursor lipid II (1:1 molar ratio) thus inhibiting cell wall synthesis (PubMed:20508130). It does not disrupt cell membranes (PubMed:20508130). Is especially active against numerous clinical isolates of S.pneumoniae, including all 90 different serotypes and isolates resistant to clinically used antibiotics (PubMed:16222292). In vitro, shows considerable selectivity for bacteria over mammalian cells (PubMed:16222292). The peptide synthesized in D-amino acids does not show antibacterial activity (PubMed:19472324). In vitro, acts on voltage-gated potassium channels by moderately inhibiting mammalian Kv1.3/KCNA3 (IC(50)=2.8 uM), and moderately inhibiting others potassium channels (PubMed:25568977).[1] [2] Publication Abstract from PubMedWe describe the use of racemic crystallography to determine the X-ray structure of the natural product plectasin, a potent antimicrobial protein recently isolated from fungus. The protein enantiomers L-plectasin and D-plectasin were prepared by total chemical synthesis; interestingly, L-plectasin showed the expected antimicrobial activity, while D-plectasin was devoid of such activity. The mirror image proteins were then used for racemic crystallization. Synchrotron X-ray diffraction data were collected to atomic resolution from a racemic plectasin crystal; the racemate crystallized in the achiral centrosymmetric space group P1 with one L-plectasin molecule and one D-plectasin molecule forming the unit cell. Dimer-like intermolecular interactions between the protein enantiomers were observed, which may account for the observed extremely low solvent content (13%-15%) and more highly ordered nature of the racemic crystals. The structure of the plectasin molecule was well defined for all 40 amino acids and was generally similar to the previously determined NMR structure, suggesting minimal impact of the crystal packing on the plectasin conformation. Racemic crystallography of synthetic protein enantiomers used to determine the X-ray structure of plectasin by direct methods.,Mandal K, Pentelute BL, Tereshko V, Thammavongsa V, Schneewind O, Kossiakoff AA, Kent SB Protein Sci. 2009 Jun;18(6):1146-54. PMID:19472324[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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