User:Eric Martz/Cavities tests: Difference between revisions

Eric Martz (talk | contribs)
x
Eric Martz (talk | contribs)
No edit summary
 
(82 intermediate revisions by the same user not shown)
Line 1: Line 1:
<applet load='Dnac_from_2ggz_a.pdb' size='500' frame='true' align='right'
<StructureSection load='' size='350' side='right' caption='' scene=''>
scene='User:Eric_Martz/Sandbox_4/Dnac_model_from_2ggz_a/6' />


The following sequence was provided for DnaC from E. coli:
*1 <scene name='31/319439/Surface_test/1'>Surface test 1</scene>: simple surface on chain A of 1d66. Colored translucent green. This surface was generated with the '''representations''' tab of the SAT.


<tt>
MKNVGDLMQR LQKMMPAHIK PAFKTGEELL AWQKEQGAIR SAALERENRA
<br>
MKMQ<b>RTFNRS GIRPLHQNCS FENYRVECEG QMNALSKARQ YVEEFDGNIA
<br>
SFIFSGKPGT GKNHLAAAIC NELLLRGKSV LIITVADIMS AMKDTFRNSG
<br>
TSEEQLLNDL SNVDLLVIDE IGVQTESKYE KVIINQIVDR RSSSKRPTGM
<br>
LTNSNMEEMT KLLGERVMDR MRLGNSLWVI FNWDSYR</b>SRV TGKEY
</tt>


This sequence was submitted to Swiss Model, which [http://tinyurl.com/4nek2q generated the homology model] shown here (<scene name='User:Eric_Martz/Sandbox_4/Dnac_model_from_2ggz_a/6'>restore initial scene</scene>) using [[2qgz]] chain A as a template, which has 18.6% sequence identity. Apparently Swiss Model used predicted secondary structure to help in the sequence alignment, but details are not clear to me. The homology model represents residues 55-237, shown in boldface in the above sequence.
*2 <scene name='31/319439/6zgi_translucen_backbone/1'>6zgi as translucent backbone, chain colors</scene> (no isosurfaces). After clicking this standard SAT-generated green link, then
<jmol>
<jmolButton>
<script>
isosurface delete; isosurface "http://proteopedia.org/wiki/images/6/67/6zgi-cavities.jvxl";
</script>
<text>Load isosurface cavities</text>
</jmolButton>
</jmol>
(From uploaded file http://proteopedia.org/wiki/images/6/67/6zgi-cavities.jvxl -- see [[Image:6zgi-cavities.jvxl]])


Swiss Model has apparently used the [[temperature value]] field in the PDB file to indicate regions that are highly unreliable, namely the regions that are <font color="red"><b>red</b></font> when the model is <scene name='User:Eric_Martz/Sandbox_4/Dnac_model_from_2ggz_a/4'>colored by temperature</scene>. These regions are shown as '''translucent white''' in the initial scene (using the Jmol command <i>select temperature >50</i>).


In order to find specific residues, or see other aspects of this homology model, please use:
*3 <jmol>
<jmolButton>
<script>
load "http://proteopedia.org/wiki/images/c/c6/6zgi-cavities.pngj";
</script>
<text>Load .PNGJ file</text>
</jmolButton>
</jmol>
(From uploaded file http://proteopedia.org/wiki/images/c/c6/6zgi-cavities.pngj -- see [http://proteopedia.org/wiki/index.php/Image:6zgi-cavities.pngj Image:6zgi-cavities.png])


[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=http%3A//proteopedia.org/wiki/images/3/3e/Dnac_from_2ggz_a.pdb View DnaC Homology Model in FirstGlance in Jmol]


The template was <scene name='User:Eric_Martz/Sandbox_4/2qgz/3'>2qgz</scene>. The portion of the template used was Glu107-Arg300. Only the amino-terminal 6 residues were not used as template (translucent). Note that there are <scene name='User:Eric_Martz/Sandbox_4/2qgz/5'>three loops</scene> in this segment of the template that lack coordinates due to [[disorder]] in the crystal (marked with spacefilled alpha-carbon atoms).
*4 <jmol>
<jmolLink>
<script>
load "http://proteopedia.org/wiki/images/c/c6/6zgi-cavities.pngj";
</script>
<text>Green link loading uploaded PNGJ file</text>
</jmolLink>
</jmol>. SAT not involved. PNGJ file generated externally in the [[Jmol/Application|Jmol Java application]], then uploaded to Proteopedia as for the previous item above.


The missing loops are 202-205 (NGSV), 226-231 (EQATSW), and 268-275 (TIKGSDET). These gaps, which occur between the residues marked /\ below, were apparently ignored in making the model, which has a continuous main chain.


Alignment produced by Swiss Model, used in making the 3D model:
*5 <scene name='31/319439/6zgi_cavities_from_pngj/1'>Test dropping pngj with cavities into SAT</scene>, then saving scene. (No molecule loaded with the SAT "load molecule" tab.)
<pre>
                                                |    | |  |    ||
TARGET    55            R TFNRSGIRPL HQNCSFENYR VECEGQMNAL SKARQYVEEF
2qgzA    100  qkqaais--e riqlvslpks yrhihlsdid vnnasrmeaf saildfveqy
                                                                     
TARGET                    sssss    h h            hhhhhhh hhhhhhhhh
2qgzA              hhh  h  sss    h h            hhhhhhh hhhhhhhhh


                            |        | ||  ||    | |              |
TARGET    96    DGN-IASFIF SGKPGTGKNH LAAAICNELL L-RGKSVLII TVADIMSAMK
2qgzA    148  psaeqkglyl ygdmgigksy llaamahels ekkgvsttll hfpsfaidvk
                                                                     
TARGET                ssss ss    hhh hhhhhhhhhh h h  ssss sshhhhhhh
2qgzA                ssss ss    hhh hhhhhhhhhh hh    ssss sshhhhhhh


                                ||
Tested in Firefox (current version) on macOS Mojave, mid-2014 MacBook Pro, 2.2 GHz Intel Core i7.
TARGET    144  DTFRNSGTSE EQLLNDLSNV DLLVIDEIGV QTESKYEKVI INQIVDRRSS
2qgzA    198  naiske---- --eidavknv pvlilddiga vrde-----v lqvilqyrml
                  /\                          / \
TARGET                        hhh    ssssss              hhhhhhhhhh
2qgzA                        hh  h    ssssss              hhhhhhhhhh


*6 <scene name='31/319439/6zgi_cavities/1'>Cavities in coronavirus spike protein 6zgi</scene>. It took 8.5 min to generate the cavity isosurfaces after I entered the command "isosurface minset 100 interior cavity 3.0 10.0" into the command slot in the SAT. (This command takes ~45 sec in the Jmol Java app which is therefore 11-fold faster for this operation.) After clicking this green link, I waited 11 min and the scene still did not appear. So I think the isosurfaces are being generated again when the green link is clicked.


TARGET    194  SKRPTGMLTN SNMEEMTKLL ---GERVMDR MRLGNSLWVI FNWDSYR 
2qgzA    247  eelptfftsn ysfadlerkw awqakrvmer vr-ylarefh leganrr- 
                                      /\
TARGET          h  ssssss    hhhhh          hhhh hh  ssssss s       
2qgzA          h  ssssss    hhhh          hhhh hh hh ssss s
</pre>


Below is the sequence with ATOM records (coordinates) from 2QGZ, numbered 100-300, showing the gaps as "...". This sequence listing was used to locate the positions marked /\ above.
<pre>
    1 .......... .......... .......... .......... ..........
  51 .......... .......... .......... .......... .........Q
  101 KQAAISERIQ LVSLPKSYRH IHLSDIDVNN ASRMEAFSAI LDFVEQYPSA
  151 EQKGLYLYGD MGIGKSYLLA AMAHELSEKK GVSTTLLHFP SFAIDVKNAI
  201 S....KEEID AVKNVPVLIL DDIGA..... .VRDEVLQVI LQYRMLEELP


  251 TFFTSNYSFA DLERKWA... .....WQAKR VMERVRYLAR EFHLEGANRR
</StructureSection>
</pre>
(Copied from Protein Explorer's sequence display.)