bio3d (version 2.1-3)

convert.pdb: Renumber and Convert Between Various PDB formats

Description

Renumber and convert between CHARMM, Amber, Gromacs and Brookhaven PDB formats.

Usage

convert.pdb(pdb, type="original",   
                renumber = FALSE, first.resno = 1, first.eleno = 1,
                consecutive=TRUE, rm.h = TRUE, rm.wat = FALSE,
                verbose=TRUE)

Arguments

pdb

a structure object of class "pdb", obtained from read.pdb.

type

output format, one of original, pdb, charmm, amber, or gromacs. The default option of original results in no conversion.

renumber

logical, if TRUE atom and residue records are renumbered using first.resno and first.eleno.

first.resno

first residue number to be used if renumber is TRUE.

first.eleno

first element number to be used if renumber is TRUE.

consecutive

logical, if TRUE renumbering will result in consecutive residue numbers spanning all chains. Otherwise new residue numbers will begin at first.resno for each chain.

rm.h

logical, if TRUE hydrogen atoms are removed.

rm.wat

logical, if TRUE water atoms are removed.

verbose

logical, if TRUE details of the conversion process are printed.

Value

• Returns a list of class "pdb", with the following components:
• atom
  a character matrix containing all atomic coordinate ATOM data, with a row per ATOM and a column per record type. See below for details of the record type naming convention (useful for accessing columns).
• het
  a character matrix containing atomic coordinate records for atoms within non-standard HET groups (see atom).
• helix
  start, end and length of H type sse, where start and end are residue numbers resno.
• sheet
  start, end and length of E type sse, where start and end are residue numbers resno.
• seqres
  sequence from SEQRES field.
• xyz
  a numeric vector of ATOM coordinate data.
• calpha
  logical vector with length equal to nrow(atom) with TRUE values indicating a C-alpha elety.

Details

Convert atom names and residue names, renumber atom and residue records, strip water and hydrogen atoms from pdb objects.

Format type can be one of ori, pdb, charmm, amber or gromacs.

References

Grant, B.J. et al. (2006) Bioinformatics 22, 2695--2696.

For a description of PDB format (version3.3) see: http://www.wwpdb.org/documentation/format33/v3.3.html.

See Also

atom.select, write.pdb, read.dcd, read.fasta.pdb, read.fasta

Examples

# Read a PDB file
pdb <- read.pdb("4q21")
pdb
head( pdb$atom[pdb$calpha,"resno"] )

# Convert to CHARMM format
new <- convert.pdb(pdb, type="amber", renumber=TRUE, first.resno=22 )
head( new$atom[new$calpha,"resno"] )

# Write a PDB file
#write.pdb(new, file="tmp4amber.pdb")