View source for 6les


==3D domain-swapped dimer of the maltose-binding protein fused to a fragment of the focal adhesion kinase==
<StructureSection load='6les' size='340' side='right'caption='[[6les]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6les]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli_K-12 Escherichia coli K-12] and [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6LES OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6LES FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.004&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=6les FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6les OCA], [https://pdbe.org/6les PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6les RCSB], [https://www.ebi.ac.uk/pdbsum/6les PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6les ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/FAK1_HUMAN FAK1_HUMAN] Note=Aberrant PTK2/FAK1 expression may play a role in cancer cell proliferation, migration and invasion, in tumor formation and metastasis. PTK2/FAK1 overexpression is seen in many types of cancer.<ref>PMID:11980671</ref> <ref>PMID:18006843</ref> <ref>PMID:17395594</ref> <ref>PMID:17431114</ref> <ref>PMID:19147981</ref> <ref>PMID:20495381</ref> <ref>PMID:16919435</ref> <ref>PMID:18677107</ref> <ref>PMID:19224453</ref> 
== Function ==
[https://www.uniprot.org/uniprot/MALE_ECOLI MALE_ECOLI] Involved in the high-affinity maltose membrane transport system MalEFGK. Initial receptor for the active transport of and chemotaxis toward maltooligosaccharides.[https://www.uniprot.org/uniprot/FAK1_HUMAN FAK1_HUMAN] Non-receptor protein-tyrosine kinase that plays an essential role in regulating cell migration, adhesion, spreading, reorganization of the actin cytoskeleton, formation and disassembly of focal adhesions and cell protrusions, cell cycle progression, cell proliferation and apoptosis. Required for early embryonic development and placenta development. Required for embryonic angiogenesis, normal cardiomyocyte migration and proliferation, and normal heart development. Regulates axon growth and neuronal cell migration, axon branching and synapse formation; required for normal development of the nervous system. Plays a role in osteogenesis and differentiation of osteoblasts. Functions in integrin signal transduction, but also in signaling downstream of numerous growth factor receptors, G-protein coupled receptors (GPCR), EPHA2, netrin receptors and LDL receptors. Forms multisubunit signaling complexes with SRC and SRC family members upon activation; this leads to the phosphorylation of additional tyrosine residues, creating binding sites for scaffold proteins, effectors and substrates. Regulates numerous signaling pathways. Promotes activation of phosphatidylinositol 3-kinase and the AKT1 signaling cascade. Promotes activation of MAPK1/ERK2, MAPK3/ERK1 and the MAP kinase signaling cascade. Promotes localized and transient activation of guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs), and thereby modulates the activity of Rho family GTPases. Signaling via CAS family members mediates activation of RAC1. Recruits the ubiquitin ligase MDM2 to P53/TP53 in the nucleus, and thereby regulates P53/TP53 activity, P53/TP53 ubiquitination and proteasomal degradation. Phosphorylates SRC; this increases SRC kinase activity. Phosphorylates ACTN1, ARHGEF7, GRB7, RET and WASL. Promotes phosphorylation of PXN and STAT1; most likely PXN and STAT1 are phosphorylated by a SRC family kinase that is recruited to autophosphorylated PTK2/FAK1, rather than by PTK2/FAK1 itself. Promotes phosphorylation of BCAR1; GIT2 and SHC1; this requires both SRC and PTK2/FAK1. Promotes phosphorylation of BMX and PIK3R1. Isoform 6 (FRNK) does not contain a kinase domain and inhibits PTK2/FAK1 phosphorylation and signaling. Its enhanced expression can attenuate the nuclear accumulation of LPXN and limit its ability to enhance serum response factor (SRF)-dependent gene transcription.<ref>PMID:10655584</ref> <ref>PMID:11331870</ref> <ref>PMID:11980671</ref> <ref>PMID:15166238</ref> <ref>PMID:15561106</ref> <ref>PMID:15895076</ref> <ref>PMID:18006843</ref> <ref>PMID:17395594</ref> <ref>PMID:16927379</ref> <ref>PMID:17431114</ref> <ref>PMID:18497331</ref> <ref>PMID:18292575</ref> <ref>PMID:18256281</ref> <ref>PMID:18206965</ref> <ref>PMID:19138410</ref> <ref>PMID:19147981</ref> <ref>PMID:20495381</ref> <ref>PMID:20109444</ref> <ref>PMID:21454698</ref> <ref>PMID:16919435</ref> <ref>PMID:18677107</ref> <ref>PMID:19224453</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The maltose-binding protein (MBP) is one of the most frequently used protein tags due to its capacity to stabilize, solubilize and even crystallize recombinant proteins that are fused to it. Given that MBP is thought to be a highly stable monomeric protein with known characteristics, fused passenger proteins are often studied without being cleaved from MBP. Here we report that a commonly used engineered MBP version (mutated to lower its surface entropy) can form interlaced dimers when fused to short protein sequences derived from the focal adhesion kinase (FAK) or the homologous protein tyrosine kinase 2 (PYK2). These MBP dimers still bind maltose and can interconvert with monomeric forms in vitro under standard conditions despite a contact surface of more than 11,000 A(2). We demonstrate that both the mutations in MBP and the fused protein sequences were required for dimer formation. The FAK and PYK2 sequences are less than 40% identical, monomeric, and did not show specific interactions with MBP, suggesting that a variety of sequences can promote this MBP dimerization. MBP dimerization was abrogated by reverting two of the eight mutations introduced in the engineered MBP. Our results provide an extreme example for induced reversible domain-swapping, with implications for protein folding dynamics. Our observations caution that passenger-promoted MBP dimerization might mislead experimental characterization of the fused protein sequences, but also suggest a simple mutation to stop this phenomenon.

Passenger sequences can promote interlaced dimers in a common variant of the maltose-binding protein.,Momin AA, Hameed UFS, Arold ST Sci Rep. 2019 Dec 31;9(1):20396. doi: 10.1038/s41598-019-56718-y. PMID:31892719<ref>PMID:31892719</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6les" style="background-color:#fffaf0;"></div>

==See Also==
*[[Maltose-binding protein 3D structures|Maltose-binding protein 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli K-12]]
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Arold ST]]
[[Category: Momin AA]]
[[Category: Shahul Hameed UF]]