PROGRAM ptntopdb

c	Reformat PTN file into PDB file

	CHARACTER*2	id
	CHARACTER*3	res
	CHARACTER*4	label
	CHARACTER*60	filnam
	REAL	mat(3,3), x(3), xo(3)

	DATA	mat/ 0.97374,  0.,  0.22767,
	1	     0.,       1.,  0.,
	2            -.35511,  0.,  0.93483/ !Cryst => Native (23) system

	WRITE (6, 1000) 'Enter PTN file name:'
1000	FORMAT (a)
	READ (5, 1000) filnam
	OPEN (unit=1, form='FORMATTED', status='OLD', readonly,
	1	file=filnam)
	WRITE (6, 1000) 'Enter PDB file name:'
	READ (5, 1000) filnam
	OPEN (unit=2, form='FORMATTED', status='NEW', file=filnam,
	1	carriagecontrol='LIST')

	num = 0
	DO WHILE (.TRUE.)
1	  READ (1, 1001, end=9) id, res, nres, label, x, b, wt
1001	  FORMAT (a2, 1x, a3, 2x, i3, a4, 5f10.5)

	  IF (id(2:2) .NE. '1') GOTO 1
c	  IF (label .NE. 'CA  ' .AND. label .NE. 'FE  ') GOTO 1
	  IF (res .EQ. 'WAT') GOTO 1

	  num = num + 1
	  DO i = 1,3
	    xo(i) = 0.
	    DO j = 1,3
	      xo(i) = xo(i) + mat(i,j)*x(j)
	    endDO
	  endDO

	  WRITE (2, 1002) num, label, res, id(1:1), nres, xo, wt, b
1002	  FORMAT ('ATOM', i7, 2x, a4, a3, 1x, a1, i4, 4x, 3f8.3, 2f6.2)

	endDO

9	CLOSE (unit=1)
	CLOSE (unit=2)

	end