atomic co - ordinates are deposited at protein data bank for free f1 and f2 ( codes 2kqb and 2kqc respectively ) , and the f1-rfa and f2-rfa complexes ( codes 2kqd and 2kqe respectively ) . assignments of h , c , n chemical shifts for free aplf 368 - 451 are deposited at biomagresbank ( code 16596 ) .
poly(adp - ribosyl)ation represents an important post - translational modification in higher eukaryotes . 
 several dna repair / checkpoint proteins possess specific par - binding zinc finger ( pbz ) modules critical for function . here 
 , we present solution structures of the two pbz modules of aplf ( aprataxin and pnk - like factor ) , revealing a novel type of zinc finger . by combining in vivo par - binding data with nmr interaction data using par fragments 
 , we suggest a structural basis for pbz - par recognition .