Binding of Synthetic LKEKK Peptide to Human T-Lymphocytes

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E. V. Navolotskaya^1*, D. V. Zinchenko¹, Y. A. Zolotarev², A. A. Kolobov³, and V. M. Lipkin¹

¹Branch of Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia; fax: +7 (0967) 33-0527; E-mail: navolotskaya@ibch.ru, elenanavolots@gmail.com

²Institute of Molecular Genetics, Russian Academy of Sciences, 123182 Moscow, Russia; fax: +7 (495) 196-0221

³State Research Institute of Highly Pure Biopreparations, Federal Biomedical Agency, 197110 St. Petersburg, Russia; fax: +7 (812) 235-5504

^* To whom correspondence should be addressed.

Received March 1, 2016; Revision received May 11, 2016

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The synthetic peptide LKEKK corresponding to sequence 16-20 of human thymosin-α₁ and 131-135 of human interferon-α₂ was labeled with tritium to specific activity 28 Ci/mol. The [³H]LKEKK bound with high affinity (K_d = 3.7 ± 0.3 nM) to donor blood T-lymphocytes. Treatment of cells with trypsin or proteinase K did not abolish [³H]LKEKK binding, suggesting the non-protein nature of the peptide receptor. The binding was inhibited by thymosin-α₁, interferon-α₂, and cholera toxin B subunit (K_i = 2.0 ± 0.3, 2.2 ± 0.2, and 3.6 ± 0.3 nM, respectively). Using [³H]LKEKK, we demonstrated the existence of a non-protein receptor common for thymosin-α₁, interferon-α₂, and cholera toxin B-subunit on donor blood T-lymphocytes.

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KEY WORDS: peptides, receptors, thymosin-α₁, interferon-α, T-lymphocytes

DOI: 10.1134/S0006297916080071

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