Linked Life Data

11063570

Source:http://linkedlifedata.com/resource/pubmed/id/11063570

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
44
pubmed:dateCreated
2000-11-28
pubmed:abstractText
Human carbonic anhydrase II (CAII) possesses a binding site for an acidic motif (D887ADD) within the carboxyl-terminal region (Ct) of the human erythrocyte chloride/bicarbonate anion exchanger, AE1. In this study, the amino acid sequence comprising this AE1 binding site was localized to the first 17 residues of CAII, which form a basic patch on the surface of the protein. Truncation of the amino terminal of CAII by five residues resulted in a 3-fold reduction in the apparent affinity of the interaction with a GST fusion protein of the Ct of AE1 (GST-Ct) measured by a sensitive microtiter plate binding assay. Further amino-terminal truncation of CAII by 17 or 24 residues caused a loss of binding. The homologous isoform CAI does not bind AE1, despite having 60% sequence identity to CAII. One major difference between the two CA isoforms, within the amino-terminal region, is a high content of histidine residues in CAII (His3, -4, -10, -15, -17) not found in CAI. Mutation of pairs of these histidines (and one lysine) in CAII to the analogous residues in CAI (H3P/H4D or K9D/H10K or H15Q/H17S), or combinations of these various double mutants, did not greatly affect binding between GST-Ct and the mutant CAII. However, when all six of the targeted CAII residues were mutated to the corresponding sequence in CAI, binding of GST-Ct was lost. These results indicate that the AE1 binding site is located within the first 17 residues of CAII, and that the interaction is mediated by electrostatic interactions involving histidine and/or lysine residues. Further specificity for the interaction of AE1 and CAII is provided by a conserved leucine residue (L886) in AE1 that, when mutated to alanine, resulted in loss of GST-Ct binding to immobilized CAII. The binding of the basic amino-terminal region of CAII to an acidic Ct in AE1 provides a structural basis for linking bicarbonate transport across the cell membrane to intracellular bicarbonate metabolism.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
7
pubmed:volume
39
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
13344-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:11063570-Amino Acid Sequence, pubmed-meshheading:11063570-Animals, pubmed-meshheading:11063570-Antiporters, pubmed-meshheading:11063570-Bicarbonates, pubmed-meshheading:11063570-Binding Sites, pubmed-meshheading:11063570-Carbonic Anhydrases, pubmed-meshheading:11063570-Cattle, pubmed-meshheading:11063570-Chickens, pubmed-meshheading:11063570-Chloride-Bicarbonate Antiporters, pubmed-meshheading:11063570-Chlorides, pubmed-meshheading:11063570-Humans, pubmed-meshheading:11063570-Mice, pubmed-meshheading:11063570-Molecular Sequence Data, pubmed-meshheading:11063570-Mutagenesis, Site-Directed, pubmed-meshheading:11063570-Peptide Fragments, pubmed-meshheading:11063570-Peptide Mapping, pubmed-meshheading:11063570-Rabbits, pubmed-meshheading:11063570-Rats, pubmed-meshheading:11063570-Sheep, pubmed-meshheading:11063570-Substrate Specificity
pubmed:year
2000
pubmed:articleTitle
Localization of the Cl-/HCO3- anion exchanger binding site to the amino-terminal region of carbonic anhydrase II.
pubmed:affiliation
Medical Research Council Group in Membrane Biology, Departments of Medicine and Biochemistry, Room 7344, Medical Sciences Building, University of Toronto, Toronto, Ontario, Canada M5S 1A8.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't