title: Three-dimensional structure of an intact human immunoglobulin.
abstract: We have examined the low-resolution structure of a complete human IgG1 using known domain coordinates from crystallographic investigations of immunoglobulin fragment structures. Our results indicate that the Fc portion of this molecule has a structure similar to that of an isolated Fc fragment, with the carbohydrate moiety playing a central role as the principal contact between the CH2 domains. Carbohydrate also forms a large part of the interface between the Fc and Fab regions. The relative orientations of the variable and constant portions of the Fab regions are intermediate between those reported previously, emphasizing the flexibility of the switch region. These data do not support a two-state allosteric model such as has been proposed for antibody effector functions.
mesh_terms: D002241:Carbohydrates / Q000032:analysis; D055598:Chemical Phenomena; D002621:Chemistry; D007140:Immunoglobulin Fab Fragments / Q000032:analysis; D007141:Immunoglobulin Fc Fragments / Q000032:analysis; D007074:Immunoglobulin G; D008958:Models, Molecular; D011487:Protein Conformation
chemical_list: D002241:Carbohydrates; D007140:Immunoglobulin Fab Fragments; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G
references.citation: Nature. 1976 Dec 2;264(5585):415-20
references.pmid: 1004567
references.citation: Hoppe Seylers Z Physiol Chem. 1976 Dec;357(10):1421-34
references.pmid: 992566
references.citation: Biophys Struct Mech. 1975 Feb 19;1(2):139-46
references.pmid: 1234024
references.citation: J Ultrastruct Res. 1972 Aug;40(3):349-65
references.pmid: 4115217
references.citation: J Mol Biol. 1967 Aug 14;27(3):615-7
references.pmid: 4167449
references.citation: Nature. 1968 Oct 19;220(5164):239-41
references.pmid: 4176457
references.citation: J Biol Chem. 1971 May 25;246(10):3259-68
references.pmid: 4324894
references.citation: Cold Spring Harb Symp Quant Biol. 1972;36:413-9
references.pmid: 4508154
references.citation: Proc Natl Acad Sci U S A. 1973 Dec;70(12):3305-10
references.pmid: 4519624
references.citation: Proc Natl Acad Sci U S A. 1974 Nov;71(11):4298-302
references.pmid: 4530984
references.citation: Eur J Biochem. 1974 Jun 15;45(2):513-24
references.pmid: 4851220
references.citation: J Mol Biol. 1974 Feb 5;82(4):587-8
references.pmid: 4817798
references.citation: Biochemistry. 1973 Nov 6;12(23):4620-31
references.pmid: 4773847
references.citation: Ann N Y Acad Sci. 1971 Dec 31;190:472-86
references.pmid: 4944966
references.citation: Prog Biophys Mol Biol. 1976;31(1):67-93
references.pmid: 822476
references.citation: Annu Rev Biochem. 1975;44:639-67
references.pmid: 806253
references.citation: Proc Natl Acad Sci U S A. 1975 Mar;72(3):819-23
references.pmid: 805424
references.citation: Hoppe Seylers Z Physiol Chem. 1976 Mar;357(3):435-45
references.pmid: 955567
references.citation: J Mol Biol. 1976 Jan 25;100(3):257-78
references.pmid: 1255713
references.citation: J Mol Biol. 1975 Nov 5;98(3):479-84
references.pmid: 1195395
references.citation: J Biol Chem. 1971 Jun 10;246(11):3760-2
references.pmid: 5578920
references.citation: J Biol Chem. 1971 Jun 10;246(11):3753-9
references.pmid: 5578919
references.citation: J Mol Biol. 1970 Aug;51(3):573-90
references.pmid: 5492607
references.citation: J Biol Chem. 1970 May 25;245(10):2763-4
references.pmid: 5445808