Protein L from Peptostreptococcus magnus binds to the kappa light chain variable domain

Research output: Contribution to journalArticle

Abstract

Protein L is an immunoglobulin light chain-binding protein expressed by some strains of the anaerobic bacterial species Peptostreptococcus magnus. The major variable region subgroups of human kappa and lambda light chains were tested for protein L binding; V kappa I, V kappa III, and V kappa IV bound protein L, whereas no binding occurred with proteins of the V kappa II subgroup or with any lambda light chain subgroups. Studies of the protein L binding capacity of naturally occurring VL fragments, and VL- and CL-related trypsin- and pepsin-derived peptides prepared from a kappa I light chain, localized the site of interaction to the VL domain. The affinity constant for the binding to an isolated V kappa I fragment was comparable to that for the native protein (Ka 0.9 x 10(9) M-1 and Ka 1.5 x 10(9) M-1, respectively). No binding occurred with CL-related fragments. Extensive reduction and alkylation of the V kappa fragment or the native kappa chain resulted in complete loss of protein L binding. Although it is possible, from comparative amino acid sequence data, to identify certain VL-framework region residues that account for the selective binding of protein L by kappa I, kappa III, and kappa IV proteins, our studies indicate that this interaction is essentially dependent upon the tertiary structural integrity of the kappa chain VL domain.

Details

Authors
Organisations
External organisations
  • University of Tennessee
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Medicinal Chemistry

Keywords

  • Amino Acid Sequence, Bacterial Proteins, Chromatography, Liquid, Electrophoresis, Polyacrylamide Gel, Humans, Immunoglobulin Variable Region, Immunoglobulin kappa-Chains, Molecular Sequence Data, Pepsin A, Peptostreptococcus, Protein Conformation, Radioimmunoassay, Trypsin, X-Ray Diffraction, Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.
Original languageEnglish
Pages (from-to)2234-9
JournalJournal of Biological Chemistry
Volume267
Issue number4
Publication statusPublished - 1992 Feb 5
Publication categoryResearch
Peer-reviewedYes