Description of ATOMS.DAT


Coordinate file (M.I.T. style), called HD-type. For subsequent use in FRODO, it is good practice to start a new residue with the atom P and to finish it with the atom O(3'). It is also helpful to group the atoms in the order phosphate, sugar, base, although the atom order within each group is irrelevant. To manipulate a HD-type file, use the program "MANIP".
With "MANIP", you can :
- add or change the occupancy,
- put the correct values for the atomic factor (KS),
- set the temperature factors per group,
- renumber the atoms,
- extract atoms by type or group,
- apply a symmetry operation.

NN,ATOM,KS,X,Y,Z,BF,Q
(I5,2X,A8,I3,5F10.4)

NN : atom #

ATOM : residue name (A1), number (I3), and atom name (A4) for example ( C21O3' ). residue and atom names must correspond to those in the dictionary (see nomenclature)

KS : atom identification for the atomic factor
= 1 ,carbon
= 2 ,nitrogen
= 3 ,oxygen
= 4 ,phosphorus
= 5 ,Mg2+
= 6 ,Na+

X,Y,Z: coordinates

BF : temperature factor

Q : occupancy

The Van der Waals contacts are checked against the values given by Ramachandran to which 0.3 has been added (see line 10 of NUCLSQ.TXT ) :

C

N

O

P

Mg

Na

C

3.40

3.20

3.10

3.70

3.60

3.60

N

3.20

3.00

3.00

3.50

2.20

2.60

O

3.10

3.00

3.10

3.50

2.20

2.60

P

3.70

3.50

3.50

3.80

3.60

3.60

Mg

3.60

2.20

2.20

3.60

3.60

3.60

Na

3.60

2.60

2.60

3.60

3.60

3.60

If KS.GT.6, then contacts as if KS=4 (i.e. P).