# Polar not charged groups - hydrogen donor or hydrogen acceptor

define bb1 *.N
define bb2 *.O

define hdprot  arg.ne,asn.nd2,cys.sg,gln.ne2,trp.ne1,tyr.oh
define haprot  asn.od1,gln.oe1,tyr.oh
define hdaprot his.nd1,his.ne2,ser.og,thr.og1
define pol_set hdprot,haprot,hdaprot
