Faculty Collaboration Database

Solution structure of a type I dockerin domain, a novel prokaryotic, extracellular calcium-binding domain. J Mol Biol 2001 Mar 30;307(3):745-53

Date

03/29/2001

Pubmed ID

11273698

DOI

10.1006/jmbi.2001.4522

Scopus ID

2-s2.0-0035970297   69 Citations

Abstract

The type I dockerin domain is responsible for incorporating its associated glycosyl hydrolase into the bacterial cellulosome, a multienzyme cellulolytic complex, via its interaction with a receptor domain (cohesin domain) of the cellulosomal scaffolding subunit. The highly conserved dockerin domain is characterized by two Ca(2+)-binding sites with sequence similarity to the EF-hand motif. Here, we present the three-dimensional solution structure of the 69 residue dockerin domain of Clostridium thermocellum cellobiohydrolase CelS. Torsion angle dynamics calculations utilizing a total of 728 NOE-derived distance constraints and 79 torsion angle restraints yielded an ensemble of 20 structures with an average backbone r.m.s.d. for residues 5 to 29 and 32 to 66 of 0.54 A from the mean structure. The structure consists of two Ca(2+)-binding loop-helix motifs connected by a linker; the E helices entering each loop of the classical EF-hand motif are absent from the dockerin domain. Each dockerin Ca(2+)-binding subdomain is stabilized by a cluster of buried hydrophobic side-chains. Structural comparisons reveal that, in its non-complexed state, the dockerin fold displays a dramatic departure from that of Ca(2+)-bound EF-hand domains. A putative cohesin-binding surface, comprised of conserved hydrophobic and basic residues, is proposed, providing new insight into cellulosome assembly.

Author List

Lytle BL, Volkman BF, Westler WM, Heckman MP, Wu JH

Author

Brian F. Volkman PhD Professor in the Biochemistry department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Amino Acid Sequence
Binding Sites
Calcium
Cell Cycle Proteins
Cellulase
Cellulose 1,4-beta-Cellobiosidase
Chromosomal Proteins, Non-Histone
Clostridium
EF Hand Motifs
Fungal Proteins
Models, Molecular
Molecular Sequence Data
Nuclear Magnetic Resonance, Biomolecular
Nuclear Proteins
Protein Binding
Protein Structure, Tertiary
Sequence Alignment