title: An additional C-terminal loop in endonuclease IV, an apurinic/apyrimidinic endonuclease, controls binding affinity to DNA.
abstract: Endonuclease IV (EndoIV) is an endonuclease that acts at apurinic/apyrimidinic (AP) sites and is classified as either long-type or short-type. The crystal structures of representative types of EndoIV from Geobacillus kaustophilus and Thermus thermophilus HB8 were determined using X-ray crystallography. G. kaustophilus EndoIV (the long type) had a higher affinity for double-stranded DNA containing an AP-site analogue than T. thermophilus EndoIV (the short type). Structural analysis of the two different EndoIVs suggested that a C-terminal DNA-recognition loop that is only present in the long type contributes to its high affinity for AP sites. A mutation analysis showed that Lys267 in the C-terminal DNA-recognition loop plays an important role in DNA binding.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Asano
authors.forename: Hirohito
authors.initials: H
authors.lastname: Ishikawa
authors.forename: Shuhei
authors.initials: S
authors.lastname: Nakane
authors.forename: Noriko
authors.initials: N
authors.lastname: Nakagawa
authors.forename: Seiki
authors.initials: S
authors.lastname: Kuramitsu
authors.forename: Ryoji
authors.initials: R
authors.lastname: Masui
mesh_terms: D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D043223:Deoxyribonuclease IV (Phage T4-Induced) / Q000737:chemistry* / Q000378:metabolism; D056506:Geobacillus / Q000201:enzymology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D016963:Thermus thermophilus / Q000201:enzymology*
chemical_list: D004247:DNA; D043223:Deoxyribonuclease IV (Phage T4-Induced)