title: Structural analysis of natural killer cell receptor protein 1 (NKR-P1) extracellular domains suggests a conserved long loop region involved in ligand specificity.
abstract: Receptor proteins at the cell surface regulate the ability of natural killer cells to recognize and kill a variety of aberrant target cells. The structural features determining the function of natural killer receptor proteins 1 (NKR-P1s) are largely unknown. In the present work, refined homology models are generated for the C-type lectin-like extracellular domains of rat NKR-P1A and NKR-P1B, mouse NKR-P1A, NKR-P1C, NKR-P1F, and NKR-P1G, and human NKR-P1 receptors. Experimental data on secondary structure, tertiary interactions, and thermal transitions are acquired for four of the proteins using Raman and infrared spectroscopy. The experimental and modeling results are in agreement with respect to the overall structures of the NKR-P1 receptor domains, while suggesting functionally significant local differences among species and isoforms. Two sequence regions that are conserved in all analyzed NKR-P1 receptors do not correspond to conserved structural elements as might be expected, but are represented by loop regions, one of which is arranged differently in the constructed models. This region displays high flexibility but is anchored by conserved sequences, suggesting that its position relative to the rest of the domain might be variable. This loop may contribute to ligand-binding specificity via a coupled conformational transition.
authors.affiliation: Laboratory of Structural Biology, Institute of Systems Biology and Ecology, Academy of Sciences of the Czech Republic, Nové Hrady, Czech Republic.
authors.forename: Zofie
authors.initials: Z
authors.lastname: Sovová
authors.forename: Vladimír
authors.initials: V
authors.lastname: Kopecký
authors.forename: Tomáš
authors.initials: T
authors.lastname: Pazderka
authors.forename: Kateřina
authors.initials: K
authors.lastname: Hofbauerová
authors.forename: Daniel
authors.initials: D
authors.lastname: Rozbeský
authors.forename: Ondřej
authors.initials: O
authors.lastname: Vaněk
authors.forename: Karel
authors.initials: K
authors.lastname: Bezouška
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Ettrich
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D017124:Conserved Sequence; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D056004:Molecular Dynamics Simulation; D008969:Molecular Sequence Data; D055651:NK Cell Lectin-Like Receptor Subfamily B / Q000737:chemistry* / Q000145:classification; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D051381:Rats; D016415:Sequence Alignment; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D040681:Structural Homology, Protein; D013816:Thermodynamics
chemical_list: D055651:NK Cell Lectin-Like Receptor Subfamily B