Abstract
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.
Original language | English (US) |
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Pages (from-to) | 79-84 |
Number of pages | 6 |
Journal | FEBS Letters |
Volume | 530 |
Issue number | 1-3 |
DOIs | |
State | Published - Oct 23 2002 |
Keywords
- Fibrous sheath
- Redox regulation
- Spermatozoon
- Thioredoxin
ASJC Scopus subject areas
- Biochemistry
- Biophysics
- Molecular Biology