title: Investigation of active form of catalytic antibody light chain 41S-2-L.
abstract: We have raised a monoclonal antibody (41S-2) against the conserved sequence, RGPDRPEGIEEEGGERDRD, of human immunodeficiency virus type1 (HIV-1) envelope gp41. That antibody light chain (41S-2-L) cleaves gp41-derived peptide (TPRGPDRPEGIEEEGGERDRD; TP41-1) with a characteristic biphasic profile composed of induction and active phases. It is considered that the conformation of 41S-2-L is changed, by such as induced fitting, to move to active phase to decompose the antigenic peptide during the induction phase. In order to investigate what happens to 41S-2-L in the induction and active phase, the cleavage reaction of the peptide by 41S-2-L was examined in detail from the viewpoint of kinetic and spectroscopic analysis. The kinetic data showed that the preferable conformational transition of 41S-2-L took place by the unimolecular reaction of 41S-2-L in the induction phase. UV-vis and fluorescence spectroscopic analysis suggested that the conformational transition leads to the generation of aggregates of 41S-2-L in the reacting solution, which causes the huge enhancement of the catalytic activity of 41S-2-L. The nuclei of the aggregates may be formed in the induction phase. The aggregates and soluble 41S-2-L are considered to be in chemical equilibrium during the cleavage reaction of the antigen.
authors.affiliation: School of Biosciences, Hiroshima Prefectural University, 562 Nanatsuka, Shobara City, Hiroshima 727-0023, Japan.
authors.forename: Yukie
authors.initials: Y
authors.lastname: Mitsuda
authors.forename: Kumi
authors.initials: K
authors.lastname: Tsuruhata
authors.forename: Emi
authors.initials: E
authors.lastname: Hifumi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Takagi
authors.forename: Taizo
authors.initials: T
authors.lastname: Uda
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D015700:HIV Envelope Protein gp41 / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D007147:Immunoglobulin Light Chains / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D007700:Kinetics; D051379:Mice; D008807:Mice, Inbred BALB C; D010446:Peptide Fragments / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013997:Time Factors
chemical_list: D000911:Antibodies, Monoclonal; D015700:HIV Envelope Protein gp41; D007147:Immunoglobulin Light Chains; D010446:Peptide Fragments