Bacterial collagen-binding domain targets undertwisted regions of collagen.
Protein Sci
; 21(10): 1554-65, 2012 Oct.
Article
em En
| MEDLINE
| ID: mdl-22898990
ABSTRACT
Clostridium histolyticum collagenase causes extensive degradation of collagen in connective tissue that results in gas gangrene. The C-terminal collagen-binding domain (CBD) of these enzymes is the minimal segment required to bind to a collagen fibril. CBD binds unidirectionally to the undertwisted C-terminus of triple helical collagen. Here, we examine whether CBD could also target undertwisted regions even in the middle of the triple helix. Collageneous peptides with an additional undertwisted region were synthesized by introducing a Gly â Ala substitution [(POG)(x) POA(POG)(y)]3, where x + y = 9 and x > 3). ¹H-¹5N heteronuclear single quantum coherence nuclear magnetic resonance (HSQC NMR) titration studies with ¹5N-labeled CBD demonstrated that the minicollagen binds to a 10 Å wide 25 Å long cleft. Six collagenous peptides each labeled with a nitroxide radical were then titrated with ¹5N-labeled CBD. CBD binds to either the Gly â Ala substitution site or to the C-terminus of each minicollagen. Small-angle X-ray scattering measurements revealed that CBD prefers to bind the Gly â Ala site to the C-terminus. The HSQC NMR spectra of ¹5N-labeled minicollagen and minicollagen with undertwisted regions were unaffected by the titration of unlabeled CBD. The results imply that CBD binds to the undertwisted region of the minicollagen but does not actively unwind the triple helix.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Bactérias
/
Colágeno
/
Colagenases
Idioma:
En
Revista:
Protein Sci
Assunto da revista:
BIOQUIMICA
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
Estados Unidos