View source for 7pvc


==The structure of Kbp.K from E. coli with potassium bound.==
<StructureSection load='7pvc' size='340' side='right'caption='[[7pvc]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7pvc]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli_K-12 Escherichia coli K-12]. This structure supersedes the now removed PDB entry [http://oca.weizmann.ac.il/oca-bin/send-pdb?obs=1&id=5fim 5fim]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7PVC OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7PVC FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=K:POTASSIUM+ION'>K</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=7pvc FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7pvc OCA], [https://pdbe.org/7pvc PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7pvc RCSB], [https://www.ebi.ac.uk/pdbsum/7pvc PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7pvc ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/KBP_ECOLI KBP_ECOLI] Highly specific potassium binding protein that is required for normal growth in the presence of high levels of external K(+). May act as a sensor of cytoplasmic K(+) concentration. Binds a single K(+) ion, which induces a large conformational change. Can also bind the larger alkali metal ions Rb(+) and Cs(+), and NH(4)(+) (PubMed:27112601). May be involved in the regulation of peptidoglycan cross-linking (PubMed:25422305).<ref>PMID:25422305</ref> <ref>PMID:27112601</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Genetically encoded potassium indicators lack optimal binding affinity for monitoring intracellular dynamics in mammalian cells. Through structure-guided design and genome mining of potassium binding proteins, we developed green fluorescent potassium indicators with a broad range of binding affinities. KRaION1 (K(+) ratiometric indicator for optical imaging based on mNeonGreen 1), based on the insertion of a potassium binding protein, Kbp, from E. coli (Ec-Kbp) into the fluorescent protein mNeonGreen, exhibits an isotonically measured Kd of 69 +/- 10 mM (mean +/- standard deviation used throughout). We identified Ec-Kbp's binding site using NMR spectroscopy to detect protein-thallium scalar couplings and refined the structure of Ec-Kbp in its potassium-bound state. Guided by this structure, we modified KRaION1, yielding KRaION1/D9N and KRaION2, which exhibit isotonically measured Kd's of 138 +/- 21 and 96 +/- 9 mM. We identified four Ec-Kbp homologues as potassium binding proteins, which yielded indicators with isotonically measured binding affinities in the 39-112 mM range. KRaIONs functioned in HeLa cells, but the Kd values differed from the isotonically measured case. We found that, by tuning the experimental conditions, Kd values could be obtained that were consistent in vitro and in vivo. We thus recommend characterizing potassium indicator Kd in the physiological context of interest before application.

Tuning the Sensitivity of Genetically Encoded Fluorescent Potassium Indicators through Structure-Guided and Genome Mining Strategies.,Torres Caban CC, Yang M, Lai C, Yang L, Subach FV, Smith BO, Piatkevich KD, Boyden ES ACS Sens. 2022 Apr 15. doi: 10.1021/acssensors.1c02201. PMID:35427452<ref>PMID:35427452</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 7pvc" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli K-12]]
[[Category: Large Structures]]
[[Category: Smith BO]]