Bacterial and Arachnid Sphingomyelinases D: Comparison of Biophysical and Pathological Activities

Sphingomyelinases D have only been identified in arachnid venoms, Corynebacteria, Arcanobacterium, Photobacterium and in the fungi Aspergillus and Coccidioides. The arachnid and bacterial enzymes share very low sequence identity and do not contain the HKD sequence motif characteristic of the phospholipase D superfamily, however, molecular modeling and circular dichroism of SMases D from Loxosceles intermedia and Corynebacterium pseudotuberculosis indicate similar folds. The phospholipase, hemolytic and necrotic activities and mice vessel permeabilities were compared and both enzymes possess the ability to hydrolyze phospholipids and also promote similar pathological reactions in the host suggesting the existence of a common underlying mechanism in tissue disruption. J. Cell. Biochem. 118:2053–2063, 2017. © 2016 Wiley Periodicals, Inc.