2anp: Difference between revisions

<table><tr><td colspan='2'>[[2anp]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Vibrio_proteolyticus Vibrio proteolyticus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2ANP OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2ANP 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]] 1.9&#8491;</td></tr>

<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=NA:SODIUM+ION'>NA</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</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=2anp FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2anp OCA], [https://pdbe.org/2anp PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2anp RCSB], [https://www.ebi.ac.uk/pdbsum/2anp PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2anp ProSAT]</span></td></tr>

    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/an/2anp_consurf.spt"</scriptWhenChecked>

    <text>to colour the structure by Evolutionary Conservation</text>

</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=2anp ConSurf].

Glutamate151 (E151) has been shown to be catalytically essential for the aminopeptidase from Vibrio proteolyticus (AAP). E151 acts as the general acid/base during the catalytic mechanism of peptide hydrolysis. However, a glutamate residue is not the only residue capable of functioning as a general acid/base during catalysis for dinuclear metallohydrolases. Recent crystallographic characterization of the D-aminopeptidase from Bacillus subtilis (DppA) revealed a histidine residue that resides in an identical position to E151 in AAP. Because the active-site ligands for DppA and AAP are identical, AAP has been used as a model enzyme to understand the mechanistic role of H115 in DppA. Substitution of E151 with histidine resulted in an active AAP enzyme exhibiting a kcat value of 2.0 min(-1), which is over 2000 times slower than r AAP (4380 min(-1)). ITC experiments revealed that ZnII binds 330 and 3 times more weakly to E151H-AAP compared to r-AAP. UV-vis and EPR spectra of CoII-loaded E151H-AAP indicated that the first metal ion resides in a hexacoordinate/pentacoordinate equilibrium environment, whereas the second metal ion is six-coordinate. pH dependence of the kinetic parameters kcat and K(m) for the hydrolysis of L-leucine p-nitroanilide (L-pNA) revealed a change in an ionization constant in the enzyme-substrate complex from 5.3 in r-AAP to 6.4 in E151H-AAP, consistent with E151 in AAP being the active-site general acid/base. Proton inventory studies at pH 8.50 indicate the transfer of one proton in the rate-limiting step of the reaction. Moreover, the X-ray crystal structure of [ZnZn(E151H-AAP)] has been solved to 1.9 A resolution, and alteration of E151 to histidine does not introduce any major conformational changes to the overall protein structure or the dinuclear ZnII active site. Therefore, a histidine residue can function as the general acid/base in hydrolysis reactions of peptides and, through analogy of the role of E151 in AAP, H115 in DppA likely shuttles a proton to the leaving group of the substrate.

Kinetic, spectroscopic, and X-ray crystallographic characterization of the functional E151H aminopeptidase from Aeromonas proteolytica.,Bzymek KP, Moulin A, Swierczek SI, Ringe D, Petsko GA, Bennett B, Holz RC Biochemistry. 2005 Sep 13;44(36):12030-40. PMID:16142900<ref>PMID:16142900</ref>

==See Also==

*[[Aminopeptidase 3D structures|Aminopeptidase 3D structures]]

== References ==

<references/>

</StructureSection>

[[Category: Large Structures]]

[[Category: Bzymek KP]]

[[Category: Holz RC]]

[[Category: Moulin A]]

[[Category: Petsko GA]]

[[Category: Ringe D]]

[[Category: Swierczek SI]]