Molecular Design, Structural Analysis and Antifungal Activity of Derivatives of Peptide CGA-N46.

Rui-Fang Li,Hui-Ru Zhang,Liang Huang,Guang-Hai Yu,Shi-Hua Chen,Shuo-Ye Yang,Ya-Nan Sun,Yan-Jie Yi,Chao-Nan Li,Zhi-Fang Lu

doi:10.1007/s12539-016-0163-x

Rui-Fang Li, Hui-Ru Zhang + Show 8 more

Open Access

https://doi.org/10.1007/s12539-016-0163-x

Copy DOI

Abstract

Chromogranin A (CGA)-N46, a derived peptide of human chromogranin A, has antifungal activity. To further research the active domain of CGA-N46, a series of derivatives were designed by successively deleting amino acid from both terminus of CGA-N46, and the amino acid sequence of each derivative was analyzed by bioinformatic software. Based on the predicted physicochemical properties of the peptides, including half-life time in mammalian reticulocytes (in vitro), yeast (in vivo) and E. coli (in vivo), instability index, aliphatic index and grand average of hydropathicity (GRAVY), the secondary structure, net charge, the distribution of hydrophobic residues and hydrophilic residues, the final derivatives CGA-N15, CGA-N16, CGA-N12 and CGA-N8 were synthesized by solid-phase peptide synthesis. The results of bioinformatic analysis showed that CGA-N46 and its derivatives were α-helix, neutral or weak positive charge, hydrophilic, and CGA-N12 and CGA-N8 were more stable than the other derivatives. The results of circular dichroism confirmed that CGA-N46 and its derived peptides displayed α-helical structure in an aqueous solution and 30 mM sodium dodecylsulfate, but α-helical contents decreased in hydrophobic lipid vesicles. CGA-N15, CGA-N16, CGA-N12 and CGA-N8 had higher antifungal activities than their mother peptide CGA-N46. Among of the derived peptides, CGA-N12 showed the least hemolytic activity. In conclusion, we have successfully identified the active domain of CGA-N46 with strong antifungal activity and weak hemolytic activity, which provides the possibility to develop a new class of antibiotics.

Highlights

Over the past decades, the widespread use of antibiotics has led to the rapid emergence of antibiotic-resistant bacteria [1, 2]
Based on the predicted physicochemical properties of the peptides, including half-life time in mammalian reticulocytes, yeast and E. coli, instability index, aliphatic index and grand average of hydropathicity (GRAVY), the secondary structure, net charge, the distribution of hydrophobic residues and hydrophilic residues, the final derivatives Chromogranin A (CGA)-N15, CGAN16, CGA-N12 and CGA-N8 were synthesized by solidphase peptide synthesis
The results of bioinformatic analysis showed that CGA-N46 and its derivatives were ahelix, neutral or weak positive charge, hydrophilic, and CGA-N12 and CGA-N8 were more stable than the other derivatives

Summary

Introduction

The widespread use of antibiotics has led to the rapid emergence of antibiotic-resistant bacteria [1, 2]. AMPs were recently determined to be potential candidates of conventional antibiotics for treating drug-resistant bacterial infections [3, 4]. These peptides have been isolated from many natural sources including microorganism, insects, animals and plants [5, 6]. Vasostatin-I (CGA1-76), an N-terminal fragment of chromogranin A, is able to kill a large variety of fungi and yeast cells in micromolar range [12]. Lugardon group synthesized several derived CGA N-terminal fragments. The results of their antifungal research indicated that the shortest active peptide corresponded to the sequence Arg47–Leu, and named chromofungin. CGA-N46, a novel antifungal peptide containing the 31st to 76th amino acids of human

Methods

Results

Conclusion