@conference{
author = "Tsibulskaya, Darya and Blagojević, Veljko and Terzić-Vidojević, Amarela and Lukić, Ivana and Vasić, Marko and Dragačević, Luka and Kojić, Milan",
year = "2024",
abstract = "Autoaggregation, the ability to self-aggregate,
is widespread among both Gram-positive and
Gram-negative bacteria. The functional role
of aggregation is not fully understood, but it
is believed to be involved in the adaptation of
bacteria to environmental conditions (PMID:
31294207). One interesting class of compounds
responsible for the aggregation of lactic
acid bacteria is aggregation factors—surface
high-molecular-weight proteins rich in threonine
and lysine (PMID: 30027759). Recently,
our research group discovered a new strain of
Streptococcus thermophilus in the mountainous
regions of Serbia, exhibiting an aggregation
phenotype. Aggregation phenotype was confirmed
visually and using microscopy. Complete
genome of Agg+ strain was sequenced using
NGS and a gene encoding a potential aggregation
factor, which was named aggS was identified.
The predicted threonine (12.5%) and lysine
(10.5%) rich protein contains 2367 amino acids,
with an average molecular weight of 255986.63
Da. AggS also contains two cysteine residues,whereas previously well-described aggregation
factors of this type did not contain any cysteine
residues. The predicted protein includes an
N-terminal YSIRK-like signal sequence and an
LPXTG cell wall anchor domain. It has 6 Mucin
binding domain repeats alternating with 6 Mub
B2-like domain repeats. Additionally, we found a
region resembling an ice-binding domain. Given
that these bacteria endure prolonged periods of
low temperatures, it can be speculated that this
surface membrane protein also helps the bacteria
withstand freezing. The fact that the alignment
using BLASTp revealed AggS to be most
closely related to an uncharacterised protein
from the genome of Lactococcus garvieae, along
with the discovery of a transposase gene sequence
upstream of the gene, suggests that the
aggregation factor was likely acquired through
horizontal gene transfer. We plan to clone it into
a shuttle vector and investigate the aggregation
phenotype using a heterologous expression system
in Lactococcus lactis, as well as explore its
other functions.",
publisher = "Serbian Society for Microbiology",
journal = "XIII Congress of microbiologists of Serbia: From biotechnology to human and planetary health",
title = "DESCRIPTION OF A NEW POTENTIAL AGGREGATION FACTOR FROM THE STREPTOCOCCUS THERMOPHILUS GENOME",
pages = "110-110",
url = "https://hdl.handle.net/21.15107/rcub_imagine_2373"
}
