Hi Bala, The program areaimol in the ccp4 package will do just that (i.e. generate a pdb file with the sasa value in the b-factor column).   Cheers,                Boaz Boaz Shaanan, Ph.D. Dept. of Life Sciences Ben-Gurion University of the Negev Beer-Sheva 84105 Israel Phone: 972-8-647-2220 ; Fax: 646-1710 Skype: boaz.shaanan‎