New insights into the recognition mechanisms of Heparan sulfate by SULF sulfatases

Through their ability to edit sulfation pattern of complex Heparan Sulfate (HS) polysaccharides, Sulf extracellular endosulfatases have emerged as critical regulators of many biological processes, including tumor progression. However, study of Sulfs remains extremely intricate and progress in characterizing their functional and structural features has been hampered by limited access to recombinant enzyme. In this study, IBS resaearchers and their collaborators unlock this critical bottleneck, by reporting an efficient expression and purification system of recombinant HSulf-2 in mammalian HEK293 cells. This novel source of enzyme enabled them to investigate the way the enzyme domain organization dictates its functional properties. By generating mutants, they confirmed previous studies that HSulf-2 catalytic (CAT) domain was sufficient to elicit arylsulfatase activity and that its hydrophilic (HD) domain was necessary to desulfate complex polysaccharides such as HS. In addition, they demonstrated for the first time that high affinity binding of HS substrates occurred through the coordinated action of both domains, and we identified and characterized 2 novel HS binding sites within the CAT domain. Altogether, their findings contribute to better understand the molecular mechanism governing HSulf-2 substrate recognition and processing. Furthermore, access to purified recombinant protein opens new perspectives for the resolution of HSulf structure and molecular features, as well as for the development of Sulf-specific inhibitors.

Expression and purification of recombinant extracellular sulfatase HSulf-2 allows deciphering of enzyme sub-domain coordinated role for the binding and 6-O-desulfation of heparan sulfate. Seffouh A, El Masri R, Makshakova O, Gout E, Hassoun ZEO, Andrieu JP, Lortat-Jacob H, Vivès RR. Cell. Mol. Life Sci. (2019).{{1007/s00018-019-03027-2