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Recombinant decorin glycoforms. Purification and structure
P Ramamurthy1, A M Hocking, D J McQuillan
1Center for Extracellular Matrix Biology, Institute of Biosciences and Technology, Texas A&M University, Houston, Texas 77030, USA.
The Journal of Biological Chemistry
|August 9, 1996
Summary
Researchers successfully expressed human decorin using a vaccinia virus system, yielding significant amounts of purified decorin proteoglycan and core protein. This study characterized decorin
Area of Science:
- Biochemistry
- Molecular Biology
- Proteomics
Background:
- Decorin is a small leucine-rich proteoglycan involved in extracellular matrix organization and cell signaling.
- Understanding decorin's structure and function is crucial for its therapeutic applications.
Purpose of the Study:
- To express and purify human decorin using a vaccinia virus/T7 bacteriophage expression system.
- To characterize the different glycoforms and structural properties of recombinant decorin.
- To investigate decorin's binding affinities for collagen and other matrix molecules.
Main Methods:
- Co-infection of HT-1080 cells with vaccinia virus vectors encoding T7 RNA polymerase and human decorin core protein.
- Metabolic labeling with [35S]methionine, [3H]glucosamine, and [35S]sulfate.
- Purification of recombinant decorin via metal affinity chromatography.
- Analysis of decorin glycoforms and molecular mass using SDS-PAGE.
- Circular dichroism spectroscopy to assess secondary structure.
- Binding assays to evaluate affinity for collagen and C1q.
Main Results:
- High-level secretion of human decorin (approx. 30 mg/10(9) cells/24 h) was achieved.
- Recombinant decorin was resolved into proteoglycan and core protein forms, with 25% secreted as core protein.
- Two core protein forms (49 and 53 kDa) were identified, differing in N-linked glycosylation.
- Deglycosylation yielded a uniform 43 kDa band.
- Native decorin proteoglycan exhibited predominantly beta-sheet secondary structure.
- Decorin demonstrated affinity for collagen types I and V, and notably for C1q.
Conclusions:
- The vaccinia virus/T7 system is effective for large-scale expression and purification of human decorin.
- Recombinant decorin retains significant secondary structure and biological binding properties.
- The structural integrity of decorin is likely essential for its biological functions in the extracellular matrix.