1b55
From Proteopedia
| Line 4: | Line 4: | ||
|PDB= 1b55 |SIZE=350|CAPTION= <scene name='initialview01'>1b55</scene>, resolution 2.4Å | |PDB= 1b55 |SIZE=350|CAPTION= <scene name='initialview01'>1b55</scene>, resolution 2.4Å | ||
|SITE= | |SITE= | ||
| - | |LIGAND= | + | |LIGAND= <scene name='pdbligand=4IP:INOSITOL-(1,3,4,5)-TETRAKISPHOSPHATE'>4IP</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene> |
| - | |ACTIVITY= [http://en.wikipedia.org/wiki/Transferase Transferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.10.1 and 2.7.10.2 2.7.10.1 and 2.7.10.2] | + | |ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Transferase Transferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.10.1 and 2.7.10.2 2.7.10.1 and 2.7.10.2] </span> |
|GENE= | |GENE= | ||
| + | |DOMAIN= | ||
| + | |RELATEDENTRY= | ||
| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1b55 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1b55 OCA], [http://www.ebi.ac.uk/pdbsum/1b55 PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1b55 RCSB]</span> | ||
}} | }} | ||
| Line 14: | Line 17: | ||
==Overview== | ==Overview== | ||
BACKGROUND: The activity of Bruton's tyrosine kinase (Btk) is important for the maturation of B cells. A variety of point mutations in this enzyme result in a severe human immunodeficiency known as X-linked agammaglobulinemia (XLA). Btk contains a pleckstrin-homology (PH) domain that specifically binds phosphatidylinositol 3,4,5-trisphosphate and, hence, responds to signalling via phosphatidylinositol 3-kinase. Point mutations in the PH domain might abolish membrane binding, preventing signalling via Btk. RESULTS: We have determined the crystal structures of the wild-type PH domain and a gain-of-function mutant E41K in complex with D-myo-inositol 1,3,4,5-tetra-kisphosphate (Ins (1,3,4,5)P4). The inositol Ins (1,3,4,5)P4 binds to a site that is similar to the inositol 1,4,5-trisphosphate binding site in the PH domain of phospholipase C-delta. A second Ins (1,3,4,5)P4 molecule is associated with the domain of the E41K mutant, suggesting a mechanism for its constitutive interaction with membrane. The affinities of Ins (1,3,4,5)P4 to the wild type (Kd = 40 nM), and several XLA-causing mutants have been measured using isothermal titration calorimetry. CONCLUSIONS: Our data provide an explanation for the specificity and high affinity of the interaction with phosphatidylinositol 3,4,5-trisphosphate and lead to a classification of the XLA mutations that reside in the Btk PH domain. Mis-sense mutations that do not simply destabilize the PH fold either directly affect the interaction with the phosphates of the lipid head group or change electrostatic properties of the lipid-binding site. One point mutation (Q127H) cannot be explained by these facts, suggesting that the PH domain of Btk carries an additional function such as interaction with a Galpha protein. | BACKGROUND: The activity of Bruton's tyrosine kinase (Btk) is important for the maturation of B cells. A variety of point mutations in this enzyme result in a severe human immunodeficiency known as X-linked agammaglobulinemia (XLA). Btk contains a pleckstrin-homology (PH) domain that specifically binds phosphatidylinositol 3,4,5-trisphosphate and, hence, responds to signalling via phosphatidylinositol 3-kinase. Point mutations in the PH domain might abolish membrane binding, preventing signalling via Btk. RESULTS: We have determined the crystal structures of the wild-type PH domain and a gain-of-function mutant E41K in complex with D-myo-inositol 1,3,4,5-tetra-kisphosphate (Ins (1,3,4,5)P4). The inositol Ins (1,3,4,5)P4 binds to a site that is similar to the inositol 1,4,5-trisphosphate binding site in the PH domain of phospholipase C-delta. A second Ins (1,3,4,5)P4 molecule is associated with the domain of the E41K mutant, suggesting a mechanism for its constitutive interaction with membrane. The affinities of Ins (1,3,4,5)P4 to the wild type (Kd = 40 nM), and several XLA-causing mutants have been measured using isothermal titration calorimetry. CONCLUSIONS: Our data provide an explanation for the specificity and high affinity of the interaction with phosphatidylinositol 3,4,5-trisphosphate and lead to a classification of the XLA mutations that reside in the Btk PH domain. Mis-sense mutations that do not simply destabilize the PH fold either directly affect the interaction with the phosphates of the lipid head group or change electrostatic properties of the lipid-binding site. One point mutation (Q127H) cannot be explained by these facts, suggesting that the PH domain of Btk carries an additional function such as interaction with a Galpha protein. | ||
| - | |||
| - | ==Disease== | ||
| - | Known diseases associated with this structure: Agammaglobulinemia, type 1, X-linked OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=300300 300300]], XLA and isolated growth hormone deficiency OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=300300 300300]] | ||
==About this Structure== | ==About this Structure== | ||
| Line 35: | Line 35: | ||
[[Category: Saraste, M.]] | [[Category: Saraste, M.]] | ||
[[Category: Surdo, P Lo.]] | [[Category: Surdo, P Lo.]] | ||
| - | [[Category: 4IP]] | ||
| - | [[Category: ZN]] | ||
| - | [[Category: 3]] | ||
| - | [[Category: 4]] | ||
| - | [[Category: 5-tetrakisphosphate]] | ||
[[Category: btk motif]] | [[Category: btk motif]] | ||
| - | [[Category: inositol 1]] | + | [[Category: inositol 1,3,4,5-tetrakisphosphate]] |
[[Category: ph domain]] | [[Category: ph domain]] | ||
[[Category: transferase]] | [[Category: transferase]] | ||
| Line 48: | Line 43: | ||
[[Category: zinc binding]] | [[Category: zinc binding]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 18:53:48 2008'' |
Revision as of 15:53, 30 March 2008
| |||||||
| , resolution 2.4Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , | ||||||
| Activity: | Transferase, with EC number and 2.7.10.2 2.7.10.1 and 2.7.10.2 | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
PH DOMAIN FROM BRUTON'S TYROSINE KINASE IN COMPLEX WITH INOSITOL 1,3,4,5-TETRAKISPHOSPHATE
Overview
BACKGROUND: The activity of Bruton's tyrosine kinase (Btk) is important for the maturation of B cells. A variety of point mutations in this enzyme result in a severe human immunodeficiency known as X-linked agammaglobulinemia (XLA). Btk contains a pleckstrin-homology (PH) domain that specifically binds phosphatidylinositol 3,4,5-trisphosphate and, hence, responds to signalling via phosphatidylinositol 3-kinase. Point mutations in the PH domain might abolish membrane binding, preventing signalling via Btk. RESULTS: We have determined the crystal structures of the wild-type PH domain and a gain-of-function mutant E41K in complex with D-myo-inositol 1,3,4,5-tetra-kisphosphate (Ins (1,3,4,5)P4). The inositol Ins (1,3,4,5)P4 binds to a site that is similar to the inositol 1,4,5-trisphosphate binding site in the PH domain of phospholipase C-delta. A second Ins (1,3,4,5)P4 molecule is associated with the domain of the E41K mutant, suggesting a mechanism for its constitutive interaction with membrane. The affinities of Ins (1,3,4,5)P4 to the wild type (Kd = 40 nM), and several XLA-causing mutants have been measured using isothermal titration calorimetry. CONCLUSIONS: Our data provide an explanation for the specificity and high affinity of the interaction with phosphatidylinositol 3,4,5-trisphosphate and lead to a classification of the XLA mutations that reside in the Btk PH domain. Mis-sense mutations that do not simply destabilize the PH fold either directly affect the interaction with the phosphates of the lipid head group or change electrostatic properties of the lipid-binding site. One point mutation (Q127H) cannot be explained by these facts, suggesting that the PH domain of Btk carries an additional function such as interaction with a Galpha protein.
About this Structure
1B55 is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Structure of the PH domain from Bruton's tyrosine kinase in complex with inositol 1,3,4,5-tetrakisphosphate., Baraldi E, Djinovic Carugo K, Hyvonen M, Surdo PL, Riley AM, Potter BV, O'Brien R, Ladbury JE, Saraste M, Structure. 1999 Apr 15;7(4):449-60. PMID:10196129
Page seeded by OCA on Sun Mar 30 18:53:48 2008
Categories: Homo sapiens | Single protein | Transferase | Baraldi, E. | Brien, R O. | Carugo, K Djinovic. | Hyvoenen, M. | Ladbury, J E. | Potter, B V.L. | Riley, A M. | Saraste, M. | Surdo, P Lo. | Btk motif | Inositol 1,3,4,5-tetrakisphosphate | Ph domain | Tyrosine-protein kinase | X-linked agammaglobulinemia | Zinc binding
