# Identification of an Unpredicted GAG-PUL in Roseihalotalea indica gen. nov. sp. nov. TK19036T and Characterization of Novel GAG-Lyases with Unique Substrate Specificities

## TL;DR

A new marine bacterium was found to have a unique gene cluster for breaking down glycosaminoglycans, with enzymes showing novel properties.

## Contribution

Discovery of a new GAG-PUL in Roseihalotalea indica and characterization of GAG-lyases with unique substrate specificities.

## Key findings

- A GAG utilization gene cluster was identified in Roseihalotalea indica TK19036T.
- RiPL38 is the first PL38 family enzyme to degrade both HA and CS.
- RiPL35 activity is optimal at 10 mM Ca2+ concentration.

## Abstract

Glycosaminoglycans (GAGs) and their degrading enzymes have extensive applications and biotechnology and medicine, and play a crucial role in the recycling of organic matter in oceans. In this study, a potential GAG utilization gene cluster was identified in the genome of a novel marine Bacteroidetes, Roseihalotalea indica gen. nov. sp. nov. TK19036T, through sole carbon source cultivation and differential proteomic analysis. Multiple GAG-lyases within this locus were purified and characterized. RiPL8 comprises a functionally unknown N-terminal domain and a catalytic C-terminal domain, exhibiting specificity for degrading hyaluronic acid (HA). The activity of RiPL35 is sensitive to Ca2+ ion concentration with an optimum at 10 mM. RiPL38 is the first reported member of the PL38 family capable of degrading HA and chondroitin sulfate (CS). In summary, our study reveals Roseihalotalea indica gen. nov. sp. nov. TK19036T harbors an unpredicted GAG degradation gene cluster, and the encoded GAG-lyases exhibit distinct substrate specificities compared to the host organism.