Overview
The TURN records identify turns and other short loop turns which normally connect other secondary structure segments.
Record Format
COLUMNS DATA TYPE FIELD DEFINITION
----------------------------------------------------------------------------------
1 - 6 Record name "TURN "
8 - 10 Integer seq Turn number; starts with 1 and
increments by one.
12 - 14 LString(3) turnId Turn identifier
16 - 18 Residue name initResName Residue name of initial residue in
turn.
20 Character initChainId Chain identifier for the chain
containing this turn.
21 - 24 Integer initSeqNum Sequence number of initial residue
in turn.
25 AChar initICode Insertion code of initial residue in
turn.
27 - 29 Residue name endResName Residue name of terminal residue of
turn.
31 Character endChainId Chain identifier for the chain
containing this turn.
32 - 35 Integer endSeqNum Sequence number of terminal residue
of turn.
36 AChar endICode Insertion code of terminal residue
of turn.
41 - 70 String comment Associated comment.
Details
* Turns include those sets of residues which form beta turns, i.e., have a hydrogen bond linking (C-O)i to (N-H)i+3. Turns which link residue i to i+2 (gamma-bends) may also be included. Others may be also be classified as turns.
* The initial residue is the N-terminus.
Verification/Validation/Value Authority Control
The validation program checks the number of residues in the given turn. PDB verifies that named residues exist in the ATOM records.
Relationships to Other Record Types
There may be related information in the REMARKs.
Example
1 2 3 4 5 6 7
1234567890123456789012345678901234567890123456789012345678901234567890
TURN 1 S1A GLY A 16 GLN A 18 SURFACE
TURN 2 FLA ILE A 50 GLY A 52 FLAP
TURN 3 S2A ILE A 66 HIS A 69 SURFACE
TURN 4 S1B GLY B 16 GLN B 18 SURFACE
TURN 5 FLB ILE B 50 GLY B 52 FLAP
TURN 6 S2B ILE B 66 HIS B 69 SURFACE