LINE:
  while ( <PROTEIN> ) {
      if ( /^VERSION\s+(\S+)/ )
      {
      # extracts the first non-space sequence after the VERSION-token
          $protname = $1;
          next LINE;
      }
      if ( /^DBSOURCE\s+.*\s(\S+)\s*$/ )
      {
      # extracts the last non-space sequence on the DBSOURCE line
          $rna = $1;
          next LINE;
      }
  }