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3 D Structure of Immunoglobulins3 D Structure of

Immunoglobulins

Hugh B. FackrellHugh B. Fackrell

Filename:Kuby05b7.pptFilename:Kuby05b7.ppt

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Assigned ReadingAssigned Reading Content Outline Content Outline Performance ObjectivesPerformance Objectives

Key termsKey terms Key ConceptsKey Concepts

Short Answer QuestionsShort Answer Questions

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ASSIGNED READING

Chapter ppChapter pp

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Antibody structureAntibody structure

Special antibodies to study structureSpecial antibodies to study structure Myeloma proteinsMyeloma proteins Bence Jones ProteinsBence Jones Proteins Monoclonal AntibodiesMonoclonal Antibodies

3D structure of antibodies3D structure of antibodies Binding siteBinding site Variability in structureVariability in structure

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Angels & DevilsAngels & Devils

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EM of IgAEM of IgA

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Antibody flexibilityAntibody flexibility

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Antibody: Space filling modelAntibody: Space filling model

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Mulptiple MyelomaMulptiple Myeloma

DiseaseDisease PlasmocytomaPlasmocytoma Cancer of antibody producing cellCancer of antibody producing cell

SymptomsSymptoms recurrent infections, anaemia, fractures, pain, recurrent infections, anaemia, fractures, pain,

bone lesionsbone lesions DetectionDetection

Electrophoresis, X-rays, blood smearElectrophoresis, X-rays, blood smear

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IgG CrystalIgG Crystal

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Myeloma InductionMyeloma Induction

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Bence Jones ProteinBence Jones Protein

Homogenous light chainsHomogenous light chains In urine of myeloma patientsIn urine of myeloma patients Easily purifiedEasily purified

Insoluble at 60 -70 Insoluble at 60 -70 ooCC Soluble at 80 Soluble at 80 ooCC

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Monoclonal AntibodiesMonoclonal Antibodies

Add information hereAdd information here

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Antibody modelAntibody model

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Problems with flexibilityProblems with flexibility

Difficult to determine entire structureDifficult to determine entire structure Hinge flexibility Hinge flexibility FragmentFragment Study FragmentStudy Fragment Assemble compositeAssemble composite

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Hinge ProlinesHinge Prolines

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IgG: Enzyme hydrolysisIgG: Enzyme hydrolysis

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Bence Jones Light chainsBence Jones Light chains

Simplest fragments to isolateSimplest fragments to isolate Easily crystallizedEasily crystallized Mimics FabMimics Fab

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Bence Jones MonomerBence Jones Monomer

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Bence Jones DimerBence Jones Dimer

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Immunoglobulin foldImmunoglobulin fold

Signature structure common to all Signature structure common to all immunoglobulinsimmunoglobulins

2 beta sheets2 beta sheets held by disulfide bondheld by disulfide bond Variations in detailed structure set Variations in detailed structure set

specificityspecificity

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Ig Fold: Variable domainsIg Fold: Variable domains

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Ig fold: Constant domainsIg fold: Constant domains

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Antigen Binding SiteAntigen Binding Site

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Structure of IgGStructure of IgG

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Ig Fold: hypervariable regionsIg Fold: hypervariable regions

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Vitamin K bound to IgGVitamin K bound to IgG

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Antigen binding to AntibodyAntigen binding to Antibody

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Antibody Strucutre: Internal motionAntibody Strucutre: Internal motion

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Antibody Structure: Internal movementAntibody Structure: Internal movement

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Antigen in AntibodyAntigen in Antibody

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Hypervariable RegionsHypervariable Regions

DiscoveryDiscovery KW plotsKW plots

Light chainsLight chains Heavy chainsHeavy chains CDR vs HVRCDR vs HVR

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Kabat & Wu PlotsKabat & Wu Plots

Why Why demonstrate details of variability of protein demonstrate details of variability of protein

sequence of similar proteinssequence of similar proteins ResultsResults

Variability = 1.0 >> no variationVariability = 1.0 >> no variation Variability = 400 >> 20 different AAVariability = 400 >> 20 different AA

Variability = Number different amino acidsFrequency of most common AA

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HV: light chainsHV: light chains

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KW plot heavy chainsKW plot heavy chains

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HV:IgGHV:IgG

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KW Heavy chains CDRKW Heavy chains CDR

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KW Light chains CDRKW Light chains CDR

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Ig SuperfamilyIg Superfamily

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Isotypes Allotypes IdiotypesIsotypes Allotypes Idiotypes

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Allosera ProductionAllosera Production

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Isotypes, Allotype IdiotypeIsotypes, Allotype Idiotype

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The EndThe End

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Performance ObjectivesPerformance Objectives

Key terms, concepts Key terms, concepts

short answersshort answers

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SHORT ANSWER QUESTIONS