title: Characterization of nine monoclonal antibodies against the Escherichia coli cyclic AMP receptor protein.
abstract: Nine hybridoma clones producing antibodies against the Escherichia coli cAMP receptor protein (CRP) have been isolated. Five of the monoclonal antibodies (Class I) had a much higher affinity for native CRP while the remaining four (Class II) bound equally well to native or denatured CRP. Using native N-terminal CRP cores, it was shown that none of the Class I monoclonal antibodies cross-reacted with the 15,000-Da CRP core, and only two bound to the 18,800-Da CRP core. The positions of the antigenic determinants for the Class II monoclonal antibodies were found by Western blotting analysis to reside in the N-proximal region of CRP. Only one monoclonal antibody strongly inhibited cAMP binding by CRP, and this was accompanied by a consequent strong inhibition of both lac DNA binding and abortive initiation by RNA polymerase. Each of the Class I monoclonal antibodies inhibited abortive initiation, and four of these antibodies also blocked the binding of cAMP X CRP to the lac DNA fragment. One Class I and one Class II monoclonal antibody bound to the cAMP X CRP X DNA complex. Two of the Class II monoclonal antibodies were without apparent effect on any of the assays used.
authors.forename: X M
authors.initials: XM
authors.lastname: Li
authors.forename: J S
authors.initials: JS
authors.lastname: Krakow
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D003429:Cross Reactions; D000242:Cyclic AMP / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000032:analysis; D004926:Escherichia coli / Q000032:analysis*; D005260:Female; D051379:Mice; D008970:Molecular Weight; D011953:Receptors, Cyclic AMP / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D011953:Receptors, Cyclic AMP; D004247:DNA; D000242:Cyclic AMP