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Tricks and improvements in Structural Genomics Chantal Abergel Structural and Genomic Information Laboratory UMR 2589-CNRS, IBSM, 31 chemin J. Aiguier, 13009 Marseille, FRANCE http://www.igs.cnrs-mrs.fr
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Microbial Genomics Bioinformatics Structural Genomics Mimivirus - T. whipplei - M. timonensis - A. baumannii Functional Genomics Experiments R. felis - R. africae - R. belli - R. massiliae, R. conorii - Exploration of microbial genomes Fundamental: surprises Directed: biomedical
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Structural genomics projects: TargetDB Escherichia coli Orfan genes Conserved genes of unknown function search for new antibiotic targets PROFUN : search for new antifungal targets Saccharomyces cerevisiae: Essential genes conserved in fungi absent in vertebrate genomes Candida albicans: Conserved in fungal pathogens absent in vertebrate genomes
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MasterDB
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~ 300 Targets
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Incomplete Factorial Design: Experimental matrix (SAmBa) Automated protocol, 12 conditions (out of 96 possible) 4 strains 3 temperatures 3 growth media
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Dot Blot for recombinant protein detection Total extracts and soluble extracts (supernatant after centrifugation) deposited on nitrocellulose membranes Use of anti (his) 5 antibody coupled HRP (Qiagen) ECL detection Dot blot statistical analysis Soluble expression condition Up to 12 proteins tested a day 90% Rosetta 17°C 2YT
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Microdialysis Affinity purification Scale up (1L culture) pI Non ionic ionic pH Overnight dialysis OD total OD soluble
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Desalting Concentration Best buffer: OD total /OD soluble ~1 λ nm Absorbance
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Electrophoresis (native, IEF, SDS) N-terminal Sequencing /Mass Spectrometry Circular Dichroïsm Dynamic light scattering Stability over time Biochemical & Biophysical Characterization Purification optimization Crystallization Stability of produced proteins ? Folding ? Protein solution monodispersity
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Combinatorial approach Functional & Structural predictions Functional & Structural predictions Bioinformatics Bioinformatics sequence homologies (BMCD) binding motif, hypothetical ligand, co-factors… Electrophoresis (native, IEF…) Electrophoresis (native, IEF…) Set of variables to be tested
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SAmBA: For crystallization prospection www.igs.cnrs.fr/samba
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Tecan diluting distributing robot 8 needles Greiner crystallization plates 5x96 wells
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Promising crystals...
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In house testing...
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Poor diffraction
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Soaking/desiccation
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YbgL Step 1
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Step 2 YbgL
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Final YbgL
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YggV Step 1
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Final YggV
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CA0996 Step 1
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Final CA0996
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What do they have in common ? (1) Mol. weight (kDa) Oligomerization Space group Cell dimension (Å) Molecule per AU YbgL26monomerC2C2 a = 70.3 b = 36.7 c = 79.7 β = 3.5 1 YggV21monomerP4 3 2 1 2 a = 78 c = 7.9 1 CA099616dodecamerP222 a = 93 b = 304.5 c = 155.5 24
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What do they have in common ? (2) Crystallization conditions CryoprotectantSoaking time Dataset Resolution ESRF YbgL Sodium citrate pH 9.15 Ethylene glycol 10% 2h FIP :2.29 Å R merge : 5.8% (28.7) YggV (NH 4 ) 2 SO 4 pH 9 glycerol 10%30 mins ID14: 2.0 Å R merge : 6.4 % (29.3) CA0996 PEG8000 LiSO 4 pH 7 glycerol 10 %15 minsFIP: 3.0
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Experimental Team Sabine Chenivesse Sophie Cozzani Céline Deregnaucourt Sandra Jeudy Marjorie Varagnol Bioinformatics Team Hiroyuki Ogata Stéphane Audic Olivier Poirot Pr. Jean-Michel Claverie
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