The Effect of Calcium and Halide Ions on the Gramicidin A Molecular State and Antimicrobial Activity

Gramicidin A (gA) forms several convertible conformations in different environments. In this study, we investigated the effect of calcium halides on the molecular state and antimicrobial activity of gramicidin A. The molecular state of gramicidin A is highly affected by the concentration of calcium salt and the type of halide anion. Gramicidin A can exist in two states that can be characterized by circular dichroism (CD), mass, nuclear magnetic resonance (NMR) and fluorescence spectroscopy. In State 1, the main molecular state of gramicidin A is as a dimer, and the addition of calcium salt can convert a mixture of four species into a single species, which is possibly a left-handed parallel double helix. In State 2, the addition of calcium halides drives gramicidin A dissociation and denaturation from a structured dimer into a rapid equilibrium of structured/unstructured monomer. We found that the abilities of dissociation and denaturation were highly dependent on the type of halide anion. The dissociation ability of calcium halides may play a vital role in the antimicrobial activity, as the structured monomeric form had the highest antimicrobial activity. Herein, our study demonstrated that the molecular state was correlated with the antimicrobial activity.

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A Left-Handed RNA Double Helix Bound by the Zα Domain of the RNA-Editing Enzyme ADAR1

Structure ◽

10.1016/j.str.2007.03.001 ◽

2007 ◽

Vol 15 (4) ◽

pp. 395-404 ◽

Cited By ~ 69

Author(s):

Diana Placido ◽

Bernard A. Brown ◽

Ky Lowenhaupt ◽

Alexander Rich ◽

Alekos Athanasiadis

Keyword(s):

Rna Editing ◽

Double Helix ◽

Left Handed ◽

Editing Enzyme

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The Antimicrobial Activity of Gramicidin A Is Associated with Hydroxyl Radical Formation

PLoS ONE ◽

10.1371/journal.pone.0117065 ◽

2015 ◽

Vol 10 (1) ◽

pp. e0117065 ◽

Cited By ~ 32

Author(s):

Je-Wen Liou ◽

Yu-Jiun Hung ◽

Chin-Hao Yang ◽

Yi-Cheng Chen

Keyword(s):

Antimicrobial Activity ◽

Hydroxyl Radical ◽

Radical Formation ◽

Gramicidin A

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The molecular structure of the left-handed Z-DNA double helix at 1.0-Å atomic resolution

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)83131-3 ◽

1989 ◽

Vol 264 (14) ◽

pp. 7921-7935

Author(s):

R V Gessner ◽

C A Frederick ◽

G J Quigley ◽

A Rich ◽

A H J Wang

Keyword(s):

Molecular Structure ◽

Double Helix ◽

Atomic Resolution ◽

Left Handed ◽

Z Dna ◽

Dna Double Helix

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Z-RNA: A Left-Handed Double Helix

Structure and Dynamics of RNA ◽

10.1007/978-1-4684-5173-3_5 ◽

1986 ◽

pp. 55-68 ◽

Cited By ~ 3

Author(s):

Ignacio Tinoco ◽

Phillip Cruz ◽

Peter Davis ◽

Kathleen Hall ◽

Charles C. Hardin ◽

...

Keyword(s):

Double Helix ◽

Left Handed

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The tetramer d(CpGpCpG) crystallizes as a left-handed double helix.

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.77.7.4016 ◽

1980 ◽

Vol 77 (7) ◽

pp. 4016-4020 ◽

Cited By ~ 117

Author(s):

J. L. Crawford ◽

F. J. Kolpak ◽

A. H. Wang ◽

G. J. Quigley ◽

J. H. van Boom ◽

...

Keyword(s):

Double Helix ◽

Left Handed

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Structures of major pilins in Clostridium perfringens demonstrate dynamic conformational change

Acta Crystallographica Section D Structural Biology ◽

10.1107/s2059798319009689 ◽

2019 ◽

Vol 75 (8) ◽

pp. 718-732 ◽

Cited By ~ 1

Author(s):

Eiji Tamai ◽

Seiichi Katayama ◽

Hiroshi Sekiya ◽

Hirofumi Nariya ◽

Shigehiro Kamitori

Keyword(s):

Conformational Change ◽

Clostridium Perfringens ◽

Bacterial Cell ◽

Double Helix ◽

Gram Positive Bacteria ◽

Left Handed ◽

Initial Adhesion ◽

Practical Model ◽

Host Tissues

Pili in Gram-positive bacteria are flexible rod proteins associated with the bacterial cell surface, and they play important roles in the initial adhesion to host tissues and colonization. The pilus shaft is formed by the covalent polymerization of major pilins, catalyzed by sortases, a family of cysteine transpeptidases. Here, X-ray structures of the major pilins from Clostridium perfringens strains 13 and SM101 and of sortase from strain SM101 are presented with biochemical analysis to detect the formation of pili in vivo. The major pilin from strain 13 adopts an elongated structure to form noncovalently linked polymeric chains in the crystal, yielding a practical model of the pilus fiber structure. The major pilin from strain SM101 adopts a novel bent structure and associates to form a left-handed twist like an antiparallel double helix in the crystal, which is likely to promote bacterial cell–cell interactions. A modeling study showed that pilin with a bent structure interacts favorably with sortase. The major pilin from strain SM101 was considered to be in an equilibrium state between an elongated and a bent structure through dynamic conformational change, which may be involved in pili-mediated colonization and sortase-mediated polymerization of pili.

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