S-layer protein of Corynebacterium glutamicum: A review on research progress and application potential

S-layer proteins are self-assembling, crystalline two-dimensional structures that form the outermost cell envelope component in numerous bacteria and archaea, which perform essential physiological roles. Recent years have witnessed extensive investigations into the structural architecture, assembly mechanisms, and biotechnological applications of S-layer proteins across diverse microbial species, such as Geobacillus stearothermophilus, Clostridioides difficile, Bacillus anthracis, Caulobacter crescentus, Deinococcus radiodurans, and lactic acid bacteria. In contrast, research on the S-layer protein of the industrial workhorse Corynebacterium glutamicum, namely PS2, appears relatively limited. The unique mycolic acid-rich outer membrane structure of this bacterium confers distinctive characteristics to its PS2 structure and anchoring properties. Recent investigations into the structure and assembly of PS2 have provided novel insights into the structural principles and assembly mechanisms of S-layer proteins and established a solid foundation for expanding the industrial applications of C. glutamicum. This review summarizes the research on C. glutamicum S-layer protein PS2 and conducts comparative analyses with other well-studied S-layer proteins to elucidate PS2's unique properties and biotechnological potentials. Collectively, these insights establish a foundational framework for advancing future mechanistic and application studies of S-layer proteins in C. glutamicum.