Pevzner IB, Agapov II, Niwa H, Maluchenko NV, Moisenovich MM, Pfüller U, Tonevitsky AG. Differences in amino acid sequences of mistletoe lectin I and III B-subunits determining carbohydrate binding specificity.
Biochim Biophys Acta Gen Subj 2005;
1675:155-64. [PMID:
15535979 DOI:
10.1016/j.bbagen.2004.09.002]
[Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2004] [Revised: 09/02/2004] [Accepted: 09/07/2004] [Indexed: 11/26/2022]
Abstract
Toxic lectins of European mistletoe Viscum album L.--MLI (viscumin), MLII and MLIII--are present in water extracts of this plant. Earlier we have cloned the full-length gene of MLIII precursor [A.G. Tonevitsky, I.I. Agapov, I.B. Pevzner, N.V. Maluchenko, M.M. Mojsenovich, U. Pfueller, M.P. Kirpichnikov, (2004) Biochemistry (Mosc.), 69 (6), 790-800, in press]. Here for the first time we report the cloning and expression in Escherichia coli cells of MLIII gene fragment encoding the carbohydrate-binding subunit. We have proved with our panel of monoclonal antibodies against ML toxins that the cloned fragment encoded MLIII B-subunit. The immunochemical and sugar-binding activities of renatured recombinant MLIII B-subunit were demonstrated in ELISA and ELLA, respectively. The comparative analysis of amino acid sequences of the cloned rMLIIIB and the B-subunits of other type II RIPs--MLI, ricin, abrin and nigrin b--was performed, revealing the main differences in primary structure of MLI and MLIII B-chains, which could determine their sugar specificity. The antigenicity analysis of MLI and MLIII B-subunits showed one epitope 25RDDDFRDGNQ34 in MLIB that is absent in MLIIIB sequence. The role of the toxic lectins and their subunits in immunological properties of mistletoe extracts is discussed.
Collapse