PDBsum entry: 1dz7

Glycoprotein

PDB id: 1dz7

Contents

Protein chain

92 a.a. *

* Residue conservation analysis

PDB id:

1dz7

Name:

Glycoprotein

Title:

Solution structure of the a-subunit of human chorionic gonadotropin [modeled without carbohydrate residues]

Structure:

Chorionic gonadotropin. Chain: a. Other_details: glycosylated at asn52 and asn78

Source:

Homo sapiens. Human. Organism_taxid: 9606. Other_details: isolated from urine of pregnant women

NMR struc:

27 models

Authors:

P.J.A.Erbel,Y.Karimi-Nejad,T.De Beer,R.Boelens, J.P.Kamerling,J.F.G.Vliegenthart

Key ref:

P.J.Erbel et al. (1999). Solution structure of the alpha-subunit of human chorionic gonadotropin. Eur J Biochem, 260, 490-498. PubMed id: 10095786 DOI: 10.1046/j.1432-1327.1999.00188.x

Date:

18-Feb-00 Release date: 29-Feb-00

Protein chain

P01215  (GLHA_HUMAN) -  Glycoprotein hormones alpha chain

Seq: 116 a.a.

Struc: 92 a.a.

 Gene Ontology (GO) functional annotation 

• Cellular component: extracellular region (2 terms)
• Biological process: developmental growth (13 terms)
• Biochemical function: hormone activity (1 term)

DOI no: 10.1046/j.1432-1327.1999.00188.x

Eur J Biochem 260:490-498 (1999)

PubMed id: 10095786

Solution structure of the alpha-subunit of human chorionic gonadotropin.

P.J.Erbel, Y.Karimi-Nejad, T.De Beer, R.Boelens, J.P.Kamerling, J.F.Vliegenthart.

ABSTRACT

The three-dimensional solution structure of the alpha-subunit in the alpha, beta heterodimeric human chorionic gonadotropin (hCG), deglycosylated with endo-beta-N-acetylglucosaminidase-B (dg-alpha hCG), was determined using 2D homonuclear and 2D heteronuclear 1H, 13C NMR spectroscopy at natural abundance in conjunction with the program package XPLOR. The distance geometry/simulated annealing protocol was modified to allow for the efficient modelling of the cystine knot motif present in alpha hCG. The protein structure was modelled with 620 interproton distance restraints and the GlcNAc residue linked to Asn78 was modelled with 30 protein-carbohydrate and 3 intraresidual NOEs. The solution structure of dg-alpha hCG is represented by an ensemble of 27 structures. In comparison to the crystal structure of the dimer, the solution structure of free dg-alpha hCG exhibits: (a) an increased structural disorder (residues 33-57); (b) a different backbone conformation near Val76 and Glu77; and (c) a larger flexibility. These differences are caused by the absence of the interactions with the beta-subunit. Consequently, in free dg-alpha hCG, compared to the intact dimer, the two hairpin loops 20-23 and 70-74 are arranged differently with respect to each other. The beta-GlcNAc(78) is tightly associated with the hydrophobic protein-core in between the beta-hairpins. This conclusion is based on the NOEs from the axial H1, H3, H5 atoms and the N-acetyl protons of beta-GlcNAc(78) to the protein-core. The hydrophobic protein-core between the beta-hairpins is thereby shielded from the solvent.

Selected figure(s)

Figure 5.
Fig. 5. Representation of the cystine knot motif of hCG. Three representative NMR structures (right), crystal structure of hCG (left). The backbone strands are indicated in purple. Only the heavy atoms of the cystine knot are displayed.

Figure 7.
Fig. 7. Overlay of the backbone atoms of the -sheets of the NMR structure onto the crystal structure. In the X-ray structure the protein-core and the GlcNAc(78) residue are coloured in red and blue, respectively. The -sheet of three representative NMR structures comprising GlcNAc(78) is displayed in white, while the second -sheet is indicated with a yellow ribbon.

The above figures are reprinted by permission from the Federation of European Biochemical Societies: Eur J Biochem (1999, 260, 490-498) copyright 1999.

Figures were selected by an automated process.