Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
2006-3-13
pubmed:databankReference
pubmed:abstractText
CsoSCA (formerly CsoS3) is a bacterial carbonic anhydrase localized in the shell of a cellular microcompartment called the carboxysome, where it converts HCO(3)(-) to CO(2) for use in carbon fixation by ribulose-bisphosphate carboxylase/oxygenase (RuBisCO). CsoSCA lacks significant sequence similarity to any of the four known classes of carbonic anhydrase (alpha, beta, gamma, or delta), and so it was initially classified as belonging to a new class, epsilon. The crystal structure of CsoSCA from Halothiobacillus neapolitanus reveals that it is actually a representative member of a new subclass of beta-carbonic anhydrases, distinguished by a lack of active site pairing. Whereas a typical beta-carbonic anhydrase maintains a pair of active sites organized within a two-fold symmetric homodimer or pair of fused, homologous domains, the two domains in CsoSCA have diverged to the point that only one domain in the pair retains a viable active site. We suggest that this defunct and somewhat diminished domain has evolved a new function, specific to its carboxysomal environment. Despite the level of sequence divergence that separates CsoSCA from the other two subclasses of beta-carbonic anhydrases, there is a remarkable level of structural similarity among active site regions, which suggests a common catalytic mechanism for the interconversion of HCO(3)(-) and CO(2). Crystal packing analysis suggests that CsoSCA exists within the carboxysome shell either as a homodimer or as extended filaments.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
17
pubmed:volume
281
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7546-55
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:16407248-Amino Acid Sequence, pubmed-meshheading:16407248-Binding Sites, pubmed-meshheading:16407248-Carbonic Anhydrases, pubmed-meshheading:16407248-Catalysis, pubmed-meshheading:16407248-Chromatography, pubmed-meshheading:16407248-Cloning, Molecular, pubmed-meshheading:16407248-Crystallography, X-Ray, pubmed-meshheading:16407248-Dimerization, pubmed-meshheading:16407248-Halothiobacillus, pubmed-meshheading:16407248-Hydrogen Bonding, pubmed-meshheading:16407248-Models, Chemical, pubmed-meshheading:16407248-Models, Molecular, pubmed-meshheading:16407248-Molecular Sequence Data, pubmed-meshheading:16407248-Protein Binding, pubmed-meshheading:16407248-Protein Conformation, pubmed-meshheading:16407248-Protein Structure, Secondary, pubmed-meshheading:16407248-Protein Structure, Tertiary, pubmed-meshheading:16407248-Recombinant Proteins, pubmed-meshheading:16407248-Sequence Homology, Amino Acid
pubmed:year
2006
pubmed:articleTitle
The structure of beta-carbonic anhydrase from the carboxysomal shell reveals a distinct subclass with one active site for the price of two.
pubmed:affiliation
Molecular Biology Institute, University of California-Los Angeles, Los Angeles, CA 90095-1570, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, N.I.H., Extramural