| Title: |
The major secreted cathepsin L1 protease of the liver fluke, Fasciola hepatica: A Leu -12 to Pro -12 replacement in the nonconserved C-terminal region of the prosegment prevents complete enzyme autoactivation and allows definition of the molecular events in prosegment removal |
| Authors: |
Stack, CM; Donnelly, S; Lowther, J; Xu, W; Collins, PR; Brinen, LS; Dalton, JP |
| Publication Year: |
2007 |
| Collection: |
University of Technology Sydney: OPUS - Open Publications of UTS Scholars |
| Subject Terms: |
Biochemistry & Molecular Biology; Animals; Dicrocoelium; Enzyme Precursors; Cathepsins; Leucine; Proline; Helminth Proteins; Amino Acid Substitution; Protein Processing; Post-Translational; Enzyme Activation; Mutation; Missense; Catalysis; Hydrogen-Ion Concentration |
| Description: |
A protease secreted by the parasitic helminth Fasciola hepatica, a 37-kDa procathepsin L1 (FheproCL1), autocatalytically processes and activates to its mature enzyme (FheCL1) over a wide pH range of 7.3 to 4.0, although activation is more rapid at low pH. Maturation initiates with cleavages of a small proportion of molecules within the central region of the prosegment, possibly by intramolecular events. However, activation to fully mature enzymes is achieved by a precise intermolecular cleavage at a Leu-12-Ser -11↓His-10 sequence within the nonconserved C-terminal region of the prosegment. The importance of this cleavage site in enzyme activation was demonstrated using an active site variant FheproCL1Gly26 (Cys26 to Gly26) and a double variant FheproCL1Pro-12/Gly26 (Leu-12 to Pro-12), and although both of these variants cannot autocatalytically process, the former is susceptible to trans-processing at a Leu -12-Ser-11↓His-10 sequence by pre-activated FheCL1, but the latter is not. Another F. hepatica secreted protease FheCL2, which, unlike FheCL1, can readily accept proline in the S2 subsite of its active site, can trans-process the double variant FheproCL1Pro-12/Gly26 by cleavage at the Pro -12-Ser-11↓His-10 sequence. Furthermore, the autoactivation of a variant enzyme with a single replacement, FheproCL1Pro-12, was very slow but was increased 40-fold in the presence of FheCL2. These studies provide a molecular insight into the regulation of FheproCL1 autocatalysis. © 2007 by The American Society for Biochemistry and Molecular Biology, Inc. |
| Document Type: |
article in journal/newspaper |
| File Description: |
application/pdf |
| Language: |
unknown |
| ISSN: |
0021-9258 |
| Relation: |
Journal of Biological Chemistry; Journal of Biological Chemistry, 2007, 282 (22), pp. 16532 - 16543; http://hdl.handle.net/10453/3557 |
| Availability: |
http://hdl.handle.net/10453/3557 |
| Accession Number: |
edsbas.38D0B668 |
| Database: |
BASE |