Abstract
Many proteins containing domains of a cysteine-rich repeated motif, such as epidermal growth factor (EGF), have been reported. Here we report strong similarity between the amino acid sequence of a plant toxin-i.e., purothionin and its homologues-and with those of a domain found in mammalian pore-forming cytoplasmic proteins: components of complement and perforin of cytotoxic T- lymphocytes or natural killer-like cytotoxic cells. These similar sequences were found to be identical to the so-called EGF-like cysteine-rich repeated motif itself. Electronmicroscopic observations indicated that, like complement and perforin, purothionin forms pores in the cytoplasmic membrane of target cells, resulting in their death within a few hours. On the basis of these sequence comparisons and physiological functions, we propose a scheme for the evolution of proteins containing modules of the cysteine-rich repeat motif.
Original language | English |
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Pages (from-to) | 707-715 |
Number of pages | 9 |
Journal | Molecular Biology and Evolution |
Volume | 9 |
Issue number | 4 |
Publication status | Published - 1992 |
Externally published | Yes |
Keywords
- cystein-rich repeat motif
- perforin
- phylogeny
- pore-forming proteins (PFP)
- purothionin
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Molecular Biology
- Genetics