Genome-based identification and characterization of a putative mucin-binding protein from the surface of Streptococcus pneumoniae.
Streptococcus pneumoniae open reading frame SP1492 encodes a surface protein that contains a novel conserved domain similar to the repeated fragments of mucin-binding proteins from lactobacilli and lactococci. To investigate the functional role(s) of this protein and its potential adhesive properties, the surface-exposed region of SP1492 was expressed in Escherichia coli, purified to homogeneity, and partially characterized by biophysical and immunological methods. Circular dichroism and sedimentation measurements confirmed that SP1492 is an all-beta protein that exists in solution as a monomer. The SP1492 protein has been shown to be expressed by S. pneumoniae and was experimentally localized to its surface. The protein functional domain binds to mucins II and III from porcine stomach and to purified submaxillary bovine gland mucin. It appears to be one of the very few unambiguous pneumococcal adhesin molecules known to date. A hypothetical model constructed by ab initio techniques predicts a novel beta-sandwich protein structure.
Bumbaca
Daniela
D
Center for Immunobiology and Vaccine Development, Children's Hospital Oakland Research Institute, Oakland, California 94609, USA.
Littlejohn
James E
JE
Nayakanti
Hannah
H
Lucas
Alexander H
AH
Rigden
Daniel J
DJ
Galperin
Michael Y
MY
Jedrzejas
Mark J
MJ
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002850:Chromatography, Gel; D002942:Circular Dichroism; D003001:Cloning, Molecular; D019295:Computational Biology; D015964:Gene Expression Regulation, Bacterial; D005818:Genetic Engineering; D016680:Genome, Bacterial; D008969:Molecular Sequence Data; D009077:Mucins / Q000378:metabolism*; D016366:Open Reading Frames; D020539:Sequence Analysis, Protein; D013296:Streptococcus pneumoniae / Q000235:genetics*
D001426:Bacterial Proteins; D002352:Carrier Proteins; D009077:Mucins