From: Jim Procter Date: Mon, 20 Feb 2017 13:32:22 +0000 (+0000) Subject: Updated info on PCA calculation (SeqSpace vs BLOSUM62) X-Git-Tag: Version_1.9.2~13 X-Git-Url: http://source.jalview.org/gitweb/?a=commitdiff_plain;h=a4445c5060ef5f400f321db59f3d42ce13a71b9d;p=jalview-manual.git Updated info on PCA calculation (SeqSpace vs BLOSUM62) Structures - new Structure Chooser figure, simplified descriptions in text. EMBL->ENA --- diff --git a/TheJalviewTutorial.tex b/TheJalviewTutorial.tex index 1019df3..ab8683d 100644 --- a/TheJalviewTutorial.tex +++ b/TheJalviewTutorial.tex @@ -2523,13 +2523,15 @@ position between each pair of sequences. The basic method is described in the Nature Structural Biology} (1995) {\bf 2}, 171-8. PMID: 7749921} and implemented at the SeqSpace server at the EBI. -Jalview provides two different options for the PCA calculation. Protein PCAs are -by default computed using BLOSUM 62 pairwise substitution scores, and nucleic -acid alignment PCAs are computed using a score model based on the identity -matrix that also treats Us and Ts as identical, to support analysis of both RNA -and DNA alignments. The {\sl Change Parameters} menu also allows the calculation -method to be toggled between SeqSpace and a variant calculation that is detailed -in Jalview's built in documentation.\footnote{See +Jalview provides two different options for the PCA calculation: SeqSpace and +Jalview mode. In SeqSpace mode, PCAs are computed using the identity matrix, and +gaps are treated as 'the unknown residue' (this actually differs from the +original SeqSpace paper, and will be adjusted in a future version of Jalview). +In Jalview mode, PCAs are computed using the chosen score matrix - which for +protein sequences, defaults to BLOSUM 62, and for nucleotides, is the +DNA identity matrix that also treats Us and Ts as identical, to support analysis +of both RNA and DNA alignments. The {\sl Change Parameters} allows the +calculation method and score models to be changed.\footnote{See \url{http://www.jalview.org/help/html/calculations/pca.html}.} \subsubsection{The PCA Viewer} @@ -2932,12 +2934,11 @@ viewing program\footnote{See the Jmol homepage \url{http://www.jmol.org} for more information.} integrated with Jalview.\footnote{Earlier versions of Jalview included MCView - a simple main chain structure viewer. Structures are visualized as an alpha carbon trace and can be viewed, rotated -and coloured in a structure viewer and the results interpreted on a sequence -alignment.} It also supports the use of UCSF Chimera, a powerful molecular -graphics system that needs separate installation. Jalview can also read PDB and -mmCIF format files directly to extract sequences and secondary structure -information, and retrieve records from the European Protein -Databank (PDBe) using the Sequence Fetcher (see \ref{fetchseq}). +and coloured using the sequence alignment.} It also supports the use of UCSF +Chimera, a powerful molecular graphics system that needs separate installation. +Jalview can also read PDB and mmCIF format files directly to extract sequences +and secondary structure information, and retrieve records from the European +Protein Databank (PDBe) using the Sequence Fetcher (see \ref{fetchseq}). \subsection{Configuring the default structure viewer} \label{configuring3dviewer} @@ -2945,25 +2946,29 @@ To configure which viewer is used when creating a new structure view, open the Structures preferences window {\sl via} {\sl Tools $\Rightarrow$ Preferences\ldots} and select either JMOL or CHIMERA as the default viewer. If you select Chimera, Jalview will search for the installed program, and if it cannot be found, -you will be prompted to locate the Chimera binary, or directed to the UCSF -Chimera download page. +you will be prompted to locate the Chimera binary, or alternately, open the UCSF +Chimera download page to obtain the software. \section{Automatic Association of PDB Structures with Sequences} -Jalview can automatically determine which structures are associated with a -sequence via its ID, and any associated database references. To do this, open -the Sequence ID popup menu and select {\sl View 3D Structure}, to open the 3D -Structure Chooser. +Jalview will attempt to automatically determine which structures are associated +with a sequence via its ID, and any associated database references. To do this +for a particular sequence or the current selection, open the Sequence ID popup +menu and select {\sl View 3D Structure}, to open the 3D Structure Chooser. %(Figure\ref{auto}). When the structure chooser is first opened, if no database identifiers are -available, Jalview will attempt to discover identifiers for the sequence and from there discover any -associated PDB structures. This can take a few seconds for each sequence and -will be performed for all selected sequences. After this is done, you can see -the added database references in a tool tip by mousing over the sequence -ID\footnote{Tip: -If sequence ID tooltip obscures your view, then use the {\sl View $\Rightarrow$ Sequence ID Tooltip $\Rightarrow$ } -submenu option to disable the display of database cross references or non-positional -features. }, now shows the Uniprot ID and any associated PDB structures. +available, Jalview will automatically perform a database reference +retrieval (See \ref{fetchdbrefs}) to discover identifiers for the +sequences to use to search the PDB. This can take a +few seconds for each sequence and will be performed for all selected +sequences.\footnote{After this is done, you can can see the added database +references in a tool tip by mousing over the sequence ID. You can use the {\sl +View $\Rightarrow$ Sequence ID Tooltip $\Rightarrow$ Show Db References } +submenu option to enable or disable these data in the tooltip.} + +Once the retrieval has finished, the structure chooser dialog will show any +available PDB entries for the selected sequences. + % % \begin{figure}[htbp] % \begin{center} @@ -2981,12 +2986,11 @@ features. }, now shows the Uniprot ID and any associated PDB structures. \subsection{Drag-and-Drop Association of PDB Files with Sequences by Filename Match} \label{multipdbfileassoc} -If one or more PDB files stored on your computer are dragged from their location -on the file browser onto an alignment window, Jalview will search the alignment -for sequences with IDs that match any of the files dropped onto the alignment. -If it discovers matches, a dialog like the one in Figure -\ref{multipdbfileassocfig} is shown, giving the option of creating associations -for the matches. +If you have PDB files stored on your computer named the same way as the +sequences in the alignment, then you can drag them from their location on the +file browser onto an alignment window. Jalview will search the alignment for +sequences with IDs that match any of the files, and offer a dialog like the one +in Figure \ref{multipdbfileassocfig}. If no associations are made, then sequences extracted from the structure will be simply added to the alignment. However, if only @@ -2999,6 +3003,12 @@ future so Jalview will automatically search for PDB files matching your sequence within a local directory. Check out \href{http://issues.jalview.org/browse/JAL-801}{Jalview issue 801}} +After associating sequences with PDB files, you can view the PDB structures by +opening the Sequence ID popup +menu and selecting {\sl View 3D Structure}. The PDB files you loaded will be +shown in the {\bf Cached Structures} view, after selecting it from the drop down +menu in the dialog box. + % there is no mention of the other footnote (#3) that appears saying: Tip: The sequence ID tooltip can often become large for heavily cross-referenced sequence IDs. Use the ... % JBP: yes there is - under 'Discovery of ' subsection. \begin{figure}[htbp] @@ -3015,27 +3025,34 @@ file with any sequences with matching IDs. } \section{Viewing Structures} -\label{viewAllStructures} -The structure viewer is launched from the sequence ID context -menu. To view a particular structure associated with a sequence in the -alignment, select the sequence and right click the mouse to open context -menu {\sl Structure $\Rightarrow$ 3D Structure data $\Rightarrow$} opens a Structure Chooser dialog box. -The second way is most useful if you want to view all structural data available for -a set of sequences in an alignment. Select all the sequence ids in the sequence -ID panel and right click the mouse to open context -menu {\sl Structure $\Rightarrow$ 3D Structure data $\Rightarrow$}. If any of -the {\bf currently selected} sequences have structures associated they will -appear in the Structure Chooser dialog box. The structures can be ranked by -different parameters, 'Best Quality' is defaul option. Select the -structures required and click {\sl View} to open a structure viewer containing -the associated structures superposed according to the alignment. - -The structure to be displayed will be downloaded or loaded from +\label{structurechooser} +The structure viewer is launched via the Sequence ID context +menu. To view structures associated with a sequence or a selected set of +sequences in the alignment, simply right click the mouse to open the context +menu, and select {\sl 3D Structure data \ldots} to open the Structure Chooser +dialog box. + +If any of +the {\bf currently selected} sequences have structures in the PDB, +they will appear in the Structure Chooser dialog box. The structures can be ranked by +different parameters, but are by default ordered according to their PDB +quality score. + +To view one or more structures, simply click {\sl +View} to open a structure viewer containing the structures selected in the +dialog. If several structures were picked, these will be shown +superposed according to the alignment. +You may find Jalview has already picked the best structure - using one of the +criteria shown in the dropdown menu (e.g. 'Best Quality', which is picked by +default). However, you are free to select your own. + +The structure(s) to be displayed will be downloaded or loaded from the local file system, and shown as a ribbon diagram coloured according to the associated sequence in the current alignment view (Figure \ref{structure} (right)). The structure can be rotated by clicking and dragging in the structure window. The structure can be zoomed using the mouse scroll wheel or by [SHIFT]-dragging the structure. + Moving the mouse cursor over a sequence to which the structure is linked in the alignment view highlights the respective residue's sidechain atoms. The sidechain highlight may be obscured by other parts of the molecule. Similarly, @@ -3050,21 +3067,23 @@ disabled for the current view. \begin{figure}[htbp] \begin{center} -\parbox{3in}{ +\parbox{4in}{ {\centering \begin{center} -\includegraphics[scale=0.5]{images/structure1.pdf} +\includegraphics[width=4in]{images/structure1.pdf} \end{center} } } -\parbox{3.2in}{ +\parbox{2.2in}{ {\centering \begin{center} -\includegraphics[width=3in]{images/structure2.pdf} +\includegraphics[width=2.2in]{images/structure2.pdf} \end{center} } } -\caption{{\bf Structure visualization} The structure viewer is launched from the sequence ID context menu (left) and allows the structure to be visualized using the embedded Jmol molecular viewer (right). } +\caption{{\bf Structure visualization} Structure viewers are launched from +the 3D Structure chooser dialog (left). Jalview shows the displayed structures +coloured according the alignment view (right). } \label{structure} \end{center} \end{figure} @@ -3718,7 +3737,7 @@ now includes some specific features for working with nucleic acid sequences and alignments. Jalview recognises nucleotide sequences and alignments based on the presence of nucleotide symbols [ACGT] in greater than 85\% of the sequences. Built in codon-translation tables can be used to translate ORFs -into peptides for further analysis. EMBL nucleotide records retrieved {\sl via} the +into peptides for further analysis. ENA nucleotide records retrieved {\sl via} the sequence fetcher (see Section \ref{fetchseq}) are also parsed in order to identify codon regions and extract peptide products. Furthermore, Jalview records mappings between protein sequences that are derived from regions of a @@ -3806,7 +3825,7 @@ window is only available when working with a nucleic acid alignment. It uses the \subsection{Linked DNA and Protein Views} \parbox{3.5in}{ -Views of alignments involving DNA sequences are linked to views of alignments containing their peptide products in a similar way to views of protein sequences and views of their associated structures. Peptides translated from cDNA that have been fetched from EMBL records for DNA contigs are linked to their `parent' coding regions. Mousing over a region of the peptide highlights codons in views showing the original coding region. +Views of alignments involving DNA sequences are linked to views of alignments containing their peptide products in a similar way to views of protein sequences and views of their associated structures. Peptides translated from cDNA that have been fetched from ENA records for DNA contigs are linked to their `parent' coding regions. Mousing over a region of the peptide highlights codons in views showing the original coding region. }\parbox{3in}{ \begin{center} %\begin{figure}[htbp] @@ -3819,21 +3838,21 @@ Views of alignments involving DNA sequences are linked to views of alignments co } -\subsection{Coding Regions from EMBL Records} +\subsection{Coding Regions from ENA Records} -Many EMBL records that can be retrieved with the sequence fetcher contain exons. -Coding regions will be marked as features on the EMBL nucleotide sequence, and +Many ENA records that can be retrieved with the sequence fetcher contain exons. +Coding regions will be marked as features on the ENA nucleotide sequence, and Uniprot database cross references will be listed in the tooltip displayed when the mouse hovers over the sequence ID. Uniprot database cross references -extracted from EMBL records are sequence cross references, and associate a +extracted from ENA records are sequence cross references, and associate a Uniprot sequence's coordinate system with the coding regions annotated on the -EMBL sequence. Jalview utilises cross-reference information in two ways. +ENA sequence. Jalview utilises cross-reference information in two ways. \subsubsection{Retrieval of Protein or DNA Cross References} -The {\sl Calculate $\Rightarrow$ Get Cross References } function is only available when Jalview recognises that there are protein/DNA cross-references present on sequences in the alignment. When selected, it retrieves the cross references from the alignment's dataset (a set of sequence and annotation metadata shared between alignments) or using the sequence database fetcher. This function can be used for EMBL sequences containing coding regions to open the Uniprot protein products in a new alignment window. The new alignment window that is opened to show the protein products will also allow dynamic highlighting of codon positions in the EMBL record for each residue in the protein product(s). +The {\sl Calculate $\Rightarrow$ Get Cross References } function is only available when Jalview recognises that there are protein/DNA cross-references present on sequences in the alignment. When selected, it retrieves the cross references from the alignment's dataset (a set of sequence and annotation metadata shared between alignments) or using the sequence database fetcher. This function can be used for ENA sequences containing coding regions to open the Uniprot protein products in a new alignment window. The new alignment window that is opened to show the protein products will also allow dynamic highlighting of codon positions in the ENA record for each residue in the protein product(s). \subsubsection{Retrieval of Protein Features on Coding Regions} -The Uniprot cross-references derived from EMBL records can be used by Jalview to visualize protein sequence features directly on nucleotide alignments. +The Uniprot cross-references derived from ENA records can be used by Jalview to visualize protein sequence features directly on nucleotide alignments. This is because the database cross references include the sequence coordinate mapping information to correspond regions on the protein sequence with that of the nucleotide contig. Jalview will use the Uniprot accession numbers associated with the sequence to retrieve features, and then map them onto the nucleotide sequence's coordinate system using the coding region location. @@ -3844,7 +3863,7 @@ the coding region location. \includegraphics[width=5in]{images/dnadasfeatures.pdf} \caption{Uniprot and PDB sum features retrieved and mapped onto -coding regions of EMBL record V00488 (an earlier version of Jalview is shown +coding regions of ENA record V00488 (an earlier version of Jalview is shown here).} \end{center} @@ -3852,7 +3871,7 @@ here).} \exercise{Visualizing Protein Features on Coding Regions} { -\exstep{Use the sequence fetcher to retrieve EMBL record D49489.} +\exstep{Use the sequence fetcher to retrieve ENA record D49489.} \exstep{Ensure that {\sl View $\Rightarrow$ Show Sequence Features} is checked and change the alignment view format to {\sl Wrapped} mode so the distinct exons can be seen.} \exstep{Open the {\sl DAS Settings} tab in the {\sl Sequence Feature Settings\ldots} diff --git a/images/structure1.pdf b/images/structure1.pdf index 0da8805..ecfb946 100644 Binary files a/images/structure1.pdf and b/images/structure1.pdf differ diff --git a/images/structure2.pdf b/images/structure2.pdf index 6cc43f3..0a10715 100644 Binary files a/images/structure2.pdf and b/images/structure2.pdf differ