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Nuclear receptor ligand-binding domains, looked at from all directions. Nuclear receptor function Nuclear receptor family NR2A2-HN4G NR2B3-RRXG NR2A5-HN4 d? NR2B1-RRXA NR2B2-RRXB NR3C1-GCR NR2A1-HNF4 NR3C4-ANDR NR2C2-TR4 NR2C1-TR2-11 NR2E1-TLX NR0B1-DAX1 NR0B2-SHP NR2E3-PNR NR3A1-ESTR NR3C2-MCR NR3A2-ERBT NR3B1-ERR1 NR6A1-GCNF NR2F6-EAR2 NR3B2-ERR2 NR5A1-SF1 NR5A2-FTF NR2F2-ARP1 NR2F1-COTF NR3C3-PRGR NR4A1-NGFI NR4A3-NOR1 NR1C1-PPAR NR4A2-NOT NR1C2-PPAS NR1H4-FAR NR1C3-PPAT NR1H3-LXR NR1D1-EAR1 NR1D2-BD73 NR1I1-VDR NR1F3-RORG NR1A2-THB1 NR1F1-ROR1 NR1I2-PXR NR1A1-THA1 NR1F2-RORB NR1B3-RRG1 NR1B2-RRB2 NR1B1-RRA1 NR1I4-CAR1-MOUSE- NR1H2-NER NR1I3-MB67 Nuclear receptor structure A-B AF-1 C C D DNA E LBD DNA binding domain – highly conserved – > 90% similarity E Ligand binding domain – conserved protein fold – > 20% sequence similarity F The questions As Organon is paying the bills, question one is, of course☺, how do ligands relate to activity? NRs can bind co-activators and co-repressors, with or without ligand being present, so what are agonists, antagonists, and inverse agonists? What is the role of each amino acid in the NR LBD? Which data handling is needed to answer these questions? 3D structure LBD (hER) Available NR data 56 structures in (PDB) >500 sequences (scattered) >1000 mutations (very scattered) >10000 ligand-binding studies (secret) Disease patterns, expression, >1000 SNPs, genetic localization, etc., etc., etc. This data must be integrated, sorted, combined, validated, understood, and used to answer our questions. Step 1 The first important step is a common numbering scheme. Whoever solves that problem once and for all should get three Nobel prices. Large data volumes Large data volumes allow us to develop new data analysis techniques. Entropy-variability analysis is a novel technique to look at very large multiple sequence alignments. Entropy-variability analysis requires ‘better’ alignments than routinely are obtained with ‘standard’ multiple sequence alignment programs. Structure-based alignment Entropy Sequence entropy Ei at position i is calculated from the frequency pi of the twenty amino acid types (p) at position i. Example: 20 Ei = - S i=1 pi ln(pi) 12345678 ASDFGHKL ASEFNHKL ASDYGHRL ASDFSHKL ASEYDHHI ATEYPHKL Entropy at 1 is zero because 0*ln(0)=0 and 1*ln(1)=0 are zero Entropy at 2 is .84*ln(.84) + .16*ln(.16) ~ .73 Entropy at 3 is 2*.5*ln(.5) ~ .69 Entropy at 5 is .32*ln(.32) + 4*.16*ln(.16) ~ 1.5 20* .05*ln(.05) ~ 3.0 Variability Sequence variability Vi is the number of amino acid types observed at position i in more than 0.5% of all sequences. Rules 1) If a residue is conserved, it is important 2) If a residue is very conserved, it is very important And with 1000 sequences: Ras Entropy-Variability 11 Red 12 Orange 22 Yellow 23 Green 33 Blue Protease Entropy-Variability 11 Red 12 Orange 22 Yellow 23 Green 33 Blue Globin Entropy-Variability 11 Red 12 Orange 22 Yellow 23 Green 33 Blue GPCR Entropy-Variability GPCR 11 G protein 12 Support 22 Signaling 23 Ligand in 33 Ligand out NR LBD Entropy-Variability 11 main function 2.8 12 first shell around main function 2.4 22 core residues (signal transduction) 2.0 23 modulator E N 1.6 T R O 1.2 P Y 33 23 33 mainly surface 0.8 22 12 0.4 11 0.0 0 2 4 6 8 10 VARIABILITY 12 14 16 18 Mutation data 1095 entries 41 receptors 12 species 3D numbers 7 sources http://www.cmbi.kun.nl/NR and click at NRMD Mutation data Transcription Diseases 20% 60% 50% 15% 40% 10% 30% 20% 5% 10% 0% 0% Box 11 Box 12 Box 22 Box 23 Box 11 Box 33 Coregulator Box 12 Box 22 Box 23 Box 33 Dimerization 40% 40% 30% 30% 20% 20% 10% 10% 0% 0% Box 11 Box 12 Box 22 Box 23 Box 33 Box 11 Box 12 Box 22 Box 23 Box 33 Mutation data No effect Ligand binding 6% 30% 5% 4% 20% 3% 10% 2% 0% 0% 1% Box 11 Box 12 Box 22 Box 23 Box 33 Box 23 Box 33 No mutations 25% 20% 15% 10% 5% 0% Box 11 Box 12 Box 22 Box 11 Box 12 Box 22 Box 23 Box 33 Ligand binding data Ligand-binding positions extracted from PDB files (nomenclature) Categorized in very frequent to not so frequent binder Which type of ligand it binds (agonist/antagonist=inverse agonist…) Ligand-binding residues LIG 1 more than 50 of 56 LIG 2 25-50 of 56 LIG 3 11-24 of 56 LIG 4 1-10 out of 56 H-bonds (~35,15,15,15) Example: role of Asp 351 agonist antagonist Ligand, cofactor and dimerization data combined with entropy-variability analysis Ligand contacting residues Cofactor contacting residues 12 3.5 10 3 2.5 8 2 6 1.5 4 1 2 0.5 0 0 Box 11 Box 12 Box 22 Box 23 Box 33 Residues involved in dimerization 7 6 5 4 3 2 1 0 Box 11 Box 12 Box 22 Box 23 Box 33 Box 11 Box 12 Box 22 Box 23 Box 33 Conclusions: Data is difficult, but we need it (sic); life would be so nice if we could do without. PDB files are the worst. Nomenclature is not homogeneous. Much data has been carefully hidden in the literature where it can only be found back with great difficulty. Residue numbering is difficult but very necessary. Variability-entropy analysis is powerful, but requires very 'good' alignments. Acknowledgements: Organon Jacob de Vlieg Jan Klomp Paula van Noort Scott Lusher UCSF Florence Horn CMBI Emmanuel Bettler Simon Folkertsma Henk-Jan Joosten Joost van Durme Wilco Fleuren Jeroen Eitjes Jeroen van Broekhuizen Richard Notebaart Richard van Hameren Ralph Brandt