The following file is an example of which format? HEADER EXTRACELLULAR MATRIX 22-JAN-98 1A3I TITLE X-RAY CRYSTALLOGRAPHIC DETERMINATION OF A COLLAGEN-LIKE TITLE 2 PEPTIDE WITH THE REPEATING SEQUENCE (PRO-PRO-GLY) ... EXPDTA X-RAY DIFFRACTION AUTHOR R.Z.KRAMER,L.VITAGLIANO,J.BELLA,R.BERISIO,L.MAZZARELLA, AUTHOR 2 B.BRODSKY,A.ZAGARI,H.M.BERMAN ... REMARK 350 BIOMOLECULE: 1 REMARK 350 APPLY THE FOLLOWING TO CHAINS: A, B, C REMARK 350 BIOMT1 1 1.000000 0.000000 0.000000 0.00000 REMARK 350 BIOMT2 1 0.000000 1.000000 0.000000 0.00000 ... SEQRES 1 A 9 PRO PRO GLY PRO PRO GLY PRO PRO GLY SEQRES 1 B 6 PRO PRO GLY PRO PRO GLY SEQRES 1 C 6 PRO PRO GLY PRO PRO GLY ... ATOM 1 N PRO A 1 8.316 21.206 21.530 1.00 17.44 N ATOM 2 CA PRO A 1 7.608 20.729 20.336 1.00 17.44 C ATOM 3 C PRO A 1 8.487 20.707 19.092 1.00 17.44 C ATOM 4 O PRO A 1 9.466 21.457 19.005 1.00 17.44 O ATOM 5 CB PRO A 1 6.460 21.723 20.211 1.00 22.26 C ... HETATM 130 C ACY 401 3.682 22.541 11.236 1.00 21.19 C HETATM 131 O ACY 401 2.807 23.097 10.553 1.00 21.19 O HETATM 132 OXT ACY 401 4.306 23.101 12.291 1.00 21.19 O ... Group