Gassericin A: a circular bacteriocin produced by Lactic acid bacteria Lactobacillus gasseri

Abstract

During the recent years extensive efforts have been made to find out bacteriocins from lactic acid bacteria (LAB) active against various food spoilage and pathogenic bacteria, and superior stabilities against heat treatments and pH variations. Bacteriocins isolated from LAB have been grouped into four classes. Circular bacteriocins which were earlier grouped among the four groups of bacteriocins, have recently been proposed to be classified into a different class, making it class V bacteriocins. Circular bacteriocins are special molecules, whose precursors must be post translationally modified to join the N to C termini with a head-to-tail peptide bond. Cyclization appears to make them less susceptible to proteolytic cleavage, high temperature and pH, and, therefore, provides enhanced stability as compared to linear bacteriocins. The advantages of circularization are also reflected by the fact that a significant number of macrocyclic natural products have found pharmaceutical applications. Circular bacteriocins were unknown two decades ago, and even to date, only a few circular bacteriocins from a diverse group of Gram positive organisms have been reported. The first example of a circular bacteriocin was enterocin AS-48, produced by Enterococcus faecalis AS-48. Gassereccin A, produced by Lactobacillus gasseri LA39, Reutericin 6 produced by Lactobacillus reuteri LA6 and Circularin A, produced by Clostridium beijerinickii ATCC 25,752, are further examples of this group of antimicrobial peptides. In the present scenario, Gassericin A can be an important tool in the food preservation owing to its properties of high pH and temperature tolerance and the fact that it is produced by LAB L. gasseri, whose many strains are proven probiotic.

In silico analysis of protein toxin and bacteriocins from Lactobacillus paracasei SD1 genome and available online databases

“…Gassericin A inhibits the growth of a wild type of toxic S . aureus isolated from mastitis milk and breast organs [71, 85, 86]. Additionally, there was another submission of Gassericin A in the L .…”

“…Additionally, there was another submission of Gassericin A in the L . paracasei Lpp41 strain, which could be an important finding, since it can be a crucial tool in food preservation due to its high pH and temperature tolerance [85]. …”

“…Three bacteriocins from L . paracasei SD1, namely, Gassericin A, LSEI_2386 and LSEI_2163, were selected to be paired and docked to the target proteins because previous studies reported [82, 87–90] that those bacteriocins exhibited antimicrobial activity and inhibited several bacteria in vitro.…”

Enemies and brothers in arms:Candida albicansand gram-positive bacteria

“…Bacteriocins are classified as small bactericidal peptides, and they are often used for food preservation (Cotter, Ross, & Hill, 2013). Their production by lactobacilli was shown in several studies, including gassericin A or salivaricins (Messaoudi et al, 2013;Pandey, Malik, Kaushik, & Singroha, 2013), and for some it is already known that they are active against Candida spp. (Kaewsrichan et al, 2006).…”

Revealing the genomic differences between two subgroups in <i>Lactobacillus gasseri</i>

“…Gassericin A was reported in L. gasseri LA39 [9], and analogs of gassericin T were reported in L. gasseri SBT2055 (gassericin T) [10], LA158 (gassericin T) [11], LF221 (gassericin K7 B) [12, 13], and EV1461 (gassericin E) [14]. The former, gassericin A, is a rare Class IIc circular bacteriocin.…”