Differential Effects of "Resurrecting" Csp Pseudoproteases during Clostridioides difficile Spore Germination.

Differential Effects of "Resurrecting" Csp Pseudoproteases during Clostridioides difficile Spore Germination. Biochem J. 2020 Apr 03;: Authors: Donnelly ML, Forster ER, Rohlfing AE, Shen A Abstract Clostridioides difficileis a spore-forming bacterial pathogen that is the leading cause of hospital-acquired gastroenteritis. C. difficileinfections begin when its spore form germinates in the gut upon sensing bile acids. These germinants induce a proteolytic signaling cascade controlled by three members of the subtilisin-like serine protease family, CspA, CspB, and CspC. Notably, even though CspC and CspA are both pseudoproteases, they are nevertheless required to sense germinants and activate the protease, CspB. Thus, CspC and CspA are part of a growing list of pseudoenzymes that play important roles in regulating cellular processes. However, despite their importance, the structural properties of pseudoenzymes that allow them to function as regulators remain poorly understood. Our recently solved crystal structure of CspC revealed that its pseudoactive site residues align closely with the catalytic triad of CspB, suggesting that it might be possible to "resurrect" the ancestral protease activity of the CspC and CspA pseudoproteases. Here, we demonstrate that restoring the catalytic triad to these pseudoproteases fails to resurrect their protease activity. We further show that the pseudoactive site substitutions differentially affect the ...
Source: The Biochemical Journal - Category: Biochemistry Authors: Tags: Biochem J Source Type: research