pdbsuperpose
Superpose 3D structures of two proteins
Syntax
pdbsuperpose(
PDB1
, PDB2
)
Dist
= pdbsuperpose(PDB1
, PDB2
)
[Dist
, RMSD
]
= pdbsuperpose(PDB1
, PDB2
)
[Dist
, RMSD
, Transf
]
= pdbsuperpose(PDB1
, PDB2
)
[Dist
, RMSD
, Transf
, PBD2TX
]
= pdbsuperpose(PDB1
, PDB2
)
...
= pdbsuperpose(...,
'ModelNum', ModelNumValue
, ...)
...
= pdbsuperpose(...,
'Scale', ScaleValue
, ...)
...
= pdbsuperpose(...,
'Translate', TranslateValue
, ...)
...
= pdbsuperpose(...,
'Reflection', ReflectionValue
, ...)
...
= pdbsuperpose(...,
'SeqAlign', SeqAlignValue
, ...)
...
= pdbsuperpose(...,
'Segment', SegmentValue
, ...)
...
= pdbsuperpose(...,
'Apply', ApplyValue
, ...)
...
= pdbsuperpose(...,
'Display', DisplayValue
, ...)
Input Arguments
PDB1 , PDB2  Protein structures represented by any of the following:

ModelNumValue  Twoelement numeric array whose elements correspond to
models in 
ScaleValue  Specifies whether to include a scaling component in the
linear transformation. Choices are 
TranslateValue  Specifies whether to include a translation component
in the linear transformation. Choices are 
ReflectionValue  Specifies whether to include a reflection component in the linear transformation. Choices are:

SeqAlignValue  Specifies whether to perform a local sequence alignment
and then use only the portions of the structures corresponding to
the segments that align to compute the linear transformation. Choices
are 
SegmentValue  Specifies the boundaries and the chain of two subsequences
to consider for computing the linear transformation.
You can omit the boundaries
to indicate the entire chain, such as in 
ApplyValue  Specifies the extent to which the linear transformation should be applied. Choices are:

DisplayValue  Warning This namevalue argument will be removed in a future release. Specifies whether to display the original

Output Arguments
Dist  Value representing a dissimilarity measure given by the sum of the squared errors
between 
RMSD  Scalar representing the root mean square distance between
the coordinates of the 
Transf  Linear transformation computed to superpose the chain
of
Note Only alpha carbon atom coordinates are used to compute the linear transformation. Tip You can use the 
PDB2TX  PDBformatted MATLAB structure that represents the coordinates
in the transformed PDB2 protein structure. 
Description
pdbsuperpose(
computes
and applies a linear transformation to superpose the coordinates of
the protein structure represented in PDB1
, PDB2
)PDB2
to
the coordinates of the protein structure represented in PDB1
. PDB1
and PDB2
are
protein structures represented by any of the following:
Character vector or string specifying a unique identifier for a protein structure record in the PDB database.
Variable containing a PDBformatted MATLAB structure, such as returned by
getpdb
orpdbread
.Character vector or string specifying a file name or a path and file name. The referenced file is a PDBformatted file. If you specify only a file name, that file must be on the MATLAB search path or in the MATLAB Current Folder.
Alpha carbon atom coordinates of single chains for each structure are considered to compute
the linear transformation (translation, reflection, orthogonal rotation, and scaling).
By default, the first chain in each structure is considered to compute the
transformation, and the transformation is applied to the entire molecule. By default,
the original PDB1
structure and the resulting transformed
PDB2
structure are displayed as separate models in the
Molecule Viewer window using the molviewer
function.
returns
a dissimilarity measure given by the sum of the squared errors between Dist
= pdbsuperpose(PDB1
, PDB2
)PDB1
and PDB2
.
For more information, see procrustes
.
[
also
returns Dist
, RMSD
]
= pdbsuperpose(PDB1
, PDB2
)RMSD
, the root mean square distance
between the coordinates of the PDB1
structure
and the transformed PDB2
structure, considering
only the atoms used to compute the linear transformation.
[
also
returns Dist
, RMSD
, Transf
]
= pdbsuperpose(PDB1
, PDB2
)Transf
, the linear transformation
computed to superpose the chain of PDB2
to
the chain of PDB1
. Transf
is
a MATLAB structure with the following fields:
T
— Orthogonal rotation and reflection component.b
— Scale component.c
— Translation component.
Note
Only alpha carbon atom coordinates are used to compute the linear transformation.
[
also
returns Dist
, RMSD
, Transf
, PBD2TX
]
= pdbsuperpose(PDB1
, PDB2
)PBD2TX
, a PDBformatted MATLAB structure
that represents the coordinates in the transformed PDB2
protein
structure.
... = pdbsuperpose(..., '
calls PropertyName
', PropertyValue
,
...)pdbsuperpose
with optional
properties that use property name/property value pairs. You can specify
one or more properties in any order. Each PropertyName
must
be enclosed in single quotation marks and is case insensitive. These
property name/property value pairs are as follows:
specifies
the models to consider in the superposition when ...
= pdbsuperpose(...,
'ModelNum', ModelNumValue
, ...)PDB1
or PDB2
contains
multiple models. ModelNumValue
is a twoelement
numeric array whose elements correspond to the models in PDB1
and PDB2
respectively.
By default, the first model in each structure is considered.
specifies
whether to include a scaling component in the linear transformation.
Choices are ...
= pdbsuperpose(...,
'Scale', ScaleValue
, ...)true
or false
(default).
specifies
whether to include a translation component in the linear transformation.
Choices are ...
= pdbsuperpose(...,
'Translate', TranslateValue
, ...)true
(default) or false
.
specifies
whether to include a reflection component in the linear transformation.
Choices are ...
= pdbsuperpose(...,
'Reflection', ReflectionValue
, ...)true
(include reflection component), false
(exclude
reflection component), or 'best'
(may or may not
include the reflection component, depending on the best fit solution).
Default is 'best'
.
specifies
whether to perform a local sequence alignment and then use only the
portions of the structures corresponding to the segments that align
to compute the linear transformation. Choices are ...
= pdbsuperpose(...,
'SeqAlign', SeqAlignValue
, ...)true
(default)
or false
.
Note
If you set the 'SeqAlign'
property to true
,
you can also specify the following properties used by the swalign
function:
'ScoringMatrix'
'GapOpen'
'ExtendGap'
For more information on these properties, see swalign
.
specifies
the boundaries and the chain of two subsequences to consider for computing
the linear transformation. ...
= pdbsuperpose(...,
'Segment', SegmentValue
, ...)SegmentValue
is
a cell array of character vectors with the following format: {'start1stop1:chain1',
'start2stop2:chain2'}
. You can omit the boundaries to indicate
the entire chain, such as in {'chain1', 'start2stop2:chain2'}
.
You can specify only one pair of segments at any given time, and the
specified segments are assumed to contain the same number of alpha
carbon atoms.
specifies
the extent to which the linear transformation should be applied. Choices
are ...
= pdbsuperpose(...,
'Apply', ApplyValue
, ...)'all'
(apply the linear transformation to the
entire PDB2 structure), 'chain'
(apply the linear
transformation to the specified chain only), or 'segment'
(apply
the linear transformation to the specified segment only). Default
is 'all'
.
specifies whether to display the original ...
= pdbsuperpose(...,
'Display', DisplayValue
, ...)PDB1
structure and
the resulting transformed PDB2TX
structure in the Molecule
Viewer window using the molviewer
function. Each structure is
represented as a separate model. Choices are true
(default) or
false
.
Examples
Use the
getpdb
function to retrieve protein structure data from the Protein Data Bank (PDB) database for two hemoglobin structures.str1 = getpdb('1dke'); str2 = getpdb('4hhb');
Superpose the first model of the two hemoglobin structures, applying the transformation to the entire molecule.
d = pdbsuperpose(str1, str2, 'model', [1 1], 'apply', 'all');
Superpose the two hemoglobin structures (each containing four chains), computing and applying the linear transformation chain by chain. Do not display the structures.
strtx = str2; chainList1 = {str1.Sequence.ChainID}; chainList2 = {str2.Sequence.ChainID}; for i = 1:4 [d(i), rmsd(i), tr(i), strtx] = pdbsuperpose(str1, strtx, ... 'segment', {chainList1{i}; chainList2{i}}, ... 'apply', 'chain', 'display', false); end
Superpose chain B on chain A of a thioredoxin structure (PDBID = 2trx), and then apply the transformation only to chain B.
[d, rmsd, tr] = pdbsuperpose('2trx', '2trx', 'segment', {'A', 'B'}, ... 'apply', 'chain') d = 0.0028 rmsd = 0.6604 tr = T: [3x3 double] b: 1 c: [109x3 double]
Superpose two calmodulin structures according to the linear transformation obtained using two 20 residuelong segments.
pdbsuperpose('1a29', '1cll', 'segment', {'1030:A', '1030:A'}) ans = 0.1945
Version History
Introduced in R2008bSee Also
getpdb
 pdbread
 pdbtransform
 swalign
 procrustes