Human spermatid‐specific thioredoxin‐1 (Sptrx‐1) is a two‐domain protein with oxidizing activity

FEBS Letters

Jiménez, Alberto³  Ladenstein, Rudolf⁴  Kieselbach, Thomas¹  Miranda-Vizuete, Antonio³  Sagemark, Johan⁴  Gustafsson, Jan-Åke³  Holmgren, Arne²  Berndt, Kurt D⁴  Tibbelin, Gudrun⁴  Ljung, Johanna²  Ren, Bin⁴  Johansson, Catrine² 

[1] Protein Analysis Unit, Department of Biosciences at NOVUM, Karolinska Institutet, S-14157 Huddinge, Sweden;Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-17177 Stockholm, Sweden;Center for Biotechnology, Department of Biosciences at NOVUM, Karolinska Institutet, S-14157 Huddinge, Sweden;Center for Structural Biochemistry, Department of Biosciences at NOVUM, Karolinska Institutet, S-14157 Huddinge, Sweden

关键词: Thioredoxin;    Spermatozoon;    Fibrous sheath;    Redox regulation;    FS;    fibrous sheath;    ODF;    outer dense fibers;    PDI;    protein disulfide isomerase;    Trx-1;    -2;    thioredoxin-1;    -2;   

DOI  :  10.1016/S0014-5793(02)03417-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Spermatid-specific thioredoxin-1 (Sptrx-1) is the first member of the thioredoxin family of proteins with a tissue-specific expression pattern, found exclusively in the tail of elongating spermatids and spermatozoa. We describe here further biochemical characterization of human Sptrx-1 protein structure and enzymatic activity. In gel filtration chromatography human Sptrx-1 eluates as a 400 kDa protein consistent with either an oligomeric form, not maintained by intermolecular disulfide bonding, and/or a highly asymmetrical structure. Analysis of circular dichroism spectra of fragments 1–360 and 361–469 and comparison to spectra of full-length Sptrx-1 supports a two-domain organization with a largely unstructured N-terminal domain and a folded thioredoxin-like C-terminal domain. Functionally, Sptrx-1 behaves as an oxidant in vitro when using selenite, but not oxidized glutathione, as electron acceptor. This oxidizing enzymatic activity suggests that Sptrx-1 might govern the stabilization (by disulfide cross-linking) of the different structures in the developing tail of spermatids and spermatozoa.

【 授权许可】

Unknown