title: EXAFS analysis of the zinc-binding domain of boar spermatidal transition protein 2.
abstract: Boar Spermatidal Transition Protein 2 (TP2; 137 amino acid residues) is supposed to play an important role in initiation of chromatin condensation and cessation of transcriptional activity during mammalian spermniogenesis. Boar TP2 has three potential zinc finger motifs and binds three atoms of zinc per molecule. However the structure of the zinc-binding domain of boar TP2 has not been completely determined. To elucidate the local structure around the zinc atoms of boar TP2, we performed an X-ray absorption fine structure (XAFS) measurement on the zinc-binding domain of TP2(TP2Z)(residues 1-103) in the fluorescence mode. By EXAFS analyses we have demonstrated that each of the three zinc atoms is coordinated by approximately two sulfur and two nitrogen atoms on average. The average Zn-S and Zn-N distances were found to be 2.36 and 2.01 A, respectively. The sulfur and nitrogen atoms are attributed to cysteine and histidine residues, respectively, from comparison of the EXAFS spectra with model compounds ZnS and ZnTPP zinc(II) tetraphenylporphyrin).
authors.affiliation: Graduate School for Science, Chiba University, Inage, Japan. tkawai@scichem.s.chem.chiba-u.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Kawai
authors.forename: T
authors.initials: T
authors.lastname: Konishi
authors.forename: T
authors.initials: T
authors.lastname: Fujikawa
authors.forename: A
authors.initials: A
authors.lastname: Sekine
authors.forename: L F
authors.initials: LF
authors.lastname: Imai
authors.forename: K
authors.initials: K
authors.lastname: Akama
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry*; D008297:Male; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D013052:Spectrometry, X-Ray Emission / Q000379:methods; D013552:Swine; D015032:Zinc / Q000737:chemistry; D016335:Zinc Fingers
chemical_list: D002868:Chromosomal Proteins, Non-Histone; C053886:spermatid transition proteins; D015032:Zinc