Structure of CBM3b of the major cellulosomal scaffoldin subunit ScaA from Acetivibrio cellulolyticus.
The carbohydrate-binding module (CBM) of the major scaffoldin subunit ScaA of the cellulosome of Acetivibrio cellulolyticus is classified as a family 3b CBM and binds strongly to cellulose. The CBM3b was overexpressed, purified and crystallized, and its three-dimensional structure was determined. The structure contained a nickel-binding site located at the N-terminal region in addition to a 'classical' CBM3b calcium-binding site. The structure was also determined independently by the SAD method using data collected at the Ni-absorption wavelength of 1.48395 Å and even at a wavelength of 0.97625 Å in a favourable case. The new scaffoldin-borne CBM3 structure reported here provides clear evidence for the proposition that a family 3b CBM may be accommodated in scaffoldin subunits and functions as the major substrate-binding entity of the cellulosome assembly.
Department of Molecular Microbiology and Biotechnology, Tel Aviv University, 69978 Tel Aviv, Israel.
Oren
O
Yaniv
Yehuda
Y
Halfon
Linda J W
LJ
Shimon
Edward A
EA
Bayer
Raphael
R
Lamed
Felix
F
Frolow
D000595:Amino Acid Sequence; D001421:Bacteria, Anaerobic / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry*; D002352:Carrier Proteins / Q000737:chemistry*; D044603:Cellulosomes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry; D016415:Sequence Alignment
D001426:Bacterial Proteins; D002352:Carrier Proteins; D021122:Protein Subunits