Citation
Wang, Hua; Fertala, Andrzej; Ratner, Buddy D.; Sage, E. Helene; & Jiang, Shaoyi (2005).
Identifying the SPARC Binding Sites on Collagen I and Procollagen I by Atomic Force Microscopy.
Anal Chem, 77(21), 6765-6771.
Abstract
SPARC (secreted protein acidic and rich in cysteine) is a matricellular protein associated with the extracellular matrix (ECM). It has been found that the production of collagen I is a requisite for the association of SPARC with ECM, and studies with SPARC-null mice indicate that SPARC plays a role in modifying the structure of collagen fibers. It is not known, however, whether SPARC interacts with the collagen I precursor, procollagen I. In this study, the binding of SPARC to collagen I and procollagen I was verified by surface plasmon resonance. The SPARC-binding sites on collagen I and procollagen I were identified by directly visualizing their complexes using tapping-mode atomic force microscopy (TM-AFM). The characteristic chain end feature in collagen I is not readily detected by AFM, so unambiguous location of the binding sites relative to the C- or N-termini is difficult. In contrast, procollagen I, with its large globular C-propeptide, permits easy identification of the C-terminus. Histograms were constructed and compared based on the distances of the bound SPARC to the C-terminus of procollagen I and to the closest end of collagen I. There is a broad distribution of SPARC binding sites on procollagen I with the most preferred binding region located ?1/3 from the C-terminus. Characterization of the SPARC-binding sites on collagen I and procollagen I provides useful information for further understanding of the functional implications of their interactions.
Reference Type
Journal Article
Secondary Title
Anal Chem
Author(s)
Wang, HuaFertala, AndrzejRatner, Buddy D.Sage, E. HeleneJiang, Shaoyi
Year Published
2005
Date Published
1130803200
Volume Number
77
Issue Number
21
Pages
6765-6771
DOI
10.1021/ac051349d
