3QB1

Interleukin-2 mutant D10

Summary for 3QB1

• Entry DOI: 10.2210/pdb3qb1/pdb
• Related: 1M47 3INK 3QAZ
• Descriptor: Interleukin-2 (1 entity in total)
• Functional Keywords: high affinity il-2 cytokine, cytokine
• Biological source: Homo sapiens (human)
• Cellular location: Secreted: P60568
• Total number of polymer chains: 8
• Total formula weight: 125817.22

Authors

Levin, A.M.,Bates, D.L.,Ring, A.M.,Lin, J.T.,Su, L.,Krieg, C.,Bowman, G.R.,Novick, P.,Pande, V.S.,Khort, H.E.,Boyman, O.,Fathman, C.G.,Garcia, K.C. (deposition date: 2011-01-12, release date: 2012-04-11, Last modification date: 2023-09-13)

Primary citation

Levin, A.M.,Bates, D.L.,Ring, A.M.,Krieg, C.,Lin, J.T.,Su, L.,Moraga, I.,Raeber, M.E.,Bowman, G.R.,Novick, P.,Pande, V.S.,Fathman, C.G.,Boyman, O.,Garcia, K.C.
Exploiting a natural conformational switch to engineer an interleukin-2 'superkine'
Nature, 484:529-533, 2012

PubMed Abstract: The immunostimulatory cytokine interleukin-2 (IL-2) is a growth factor for a wide range of leukocytes, including T cells and natural killer (NK) cells. Considerable effort has been invested in using IL-2 as a therapeutic agent for a variety of immune disorders ranging from AIDS to cancer. However, adverse effects have limited its use in the clinic. On activated T cells, IL-2 signals through a quaternary 'high affinity' receptor complex consisting of IL-2, IL-2Rα (termed CD25), IL-2Rβ and IL-2Rγ. Naive T cells express only a low density of IL-2Rβ and IL-2Rγ, and are therefore relatively insensitive to IL-2, but acquire sensitivity after CD25 expression, which captures the cytokine and presents it to IL-2Rβ and IL-2Rγ. Here, using in vitro evolution, we eliminated the functional requirement of IL-2 for CD25 expression by engineering an IL-2 'superkine' (also called super-2) with increased binding affinity for IL-2Rβ. Crystal structures of the IL-2 superkine in free and receptor-bound forms showed that the evolved mutations are principally in the core of the cytokine, and molecular dynamics simulations indicated that the evolved mutations stabilized IL-2, reducing the flexibility of a helix in the IL-2Rβ binding site, into an optimized receptor-binding conformation resembling that when bound to CD25. The evolved mutations in the IL-2 superkine recapitulated the functional role of CD25 by eliciting potent phosphorylation of STAT5 and vigorous proliferation of T cells irrespective of CD25 expression. Compared to IL-2, the IL-2 superkine induced superior expansion of cytotoxic T cells, leading to improved antitumour responses in vivo, and elicited proportionally less expansion of T regulatory cells and reduced pulmonary oedema. Collectively, we show that in vitro evolution has mimicked the functional role of CD25 in enhancing IL-2 potency and regulating target cell specificity, which has implications for immunotherapy.

PubMed: 22446627
DOI: 10.1038/nature10975

Experimental method

X-RAY DIFFRACTION (3.1 Å)