FAN1 is a DNA structure-specific nuclease involved in the processing of DNA interstrand crosslinks (ICLs). It maintains genomic stability and prevents tissue decline in several organs. This protein possesses preferential endonuclease activity toward 5' flap structures [1-5]. FAN1 is present in most eukaryotes and some bacterial sequences. It consists of four characterised domains: UBZ, SAP, TPR and VRR nuclease (Pfam:PF08774). However, monocellular eukaryote and bacterial homologues lack the UBZ domain [1]. The N-terminal helical domain of FAN1 can be subdivided in a winged-helix (WH) DNA-binding domain, represented in this entry, and a SAP domain (bacterial Pfam:PF18081 and eukaryotic Pfam:PF21169) [1-5].

1: Crystal structure of a Fanconi anemia-associated nuclease homolog bound to 5' flap DNA: basis of interstrand cross-link repair by FAN1. Gwon GH, Kim Y, Liu Y, Watson AT, Jo A, Etheridge TJ, Yuan F, Zhang Y, Kim Y, Carr AM, Cho Y; Genes Dev. 2014;28:2276-2290. PMID:25319828

2: Structural insights into 5' flap DNA unwinding and incision by the human FAN1 dimer. Zhao Q, Xue X, Longerich S, Sung P, Xiong Y; Nat Commun. 2014;5:5726. PMID:25500724

3: DNA repair. Mechanism of DNA interstrand cross-link processing by repair nuclease FAN1. Wang R, Persky NS, Yoo B, Ouerfelli O, Smogorzewska A, Elledge SJ, Pavletich NP; Science. 2014;346:1127-1130. PMID:25430771

4: Crystal structure of human Fanconi-associated nuclease 1. Yan PX, Huo YG, Jiang T; Protein Cell. 2015;6:225-228. PMID:25547363

5: Structural mechanism of DNA interstrand cross-link unhooking by the bacterial FAN1 nuclease. Jin H, Roy U, Lee G, Scharer OD, Cho Y; J Biol Chem. 2018;293:6482-6496. PMID:29514982