1. Two novel antifungal peptides distinct with a five-disulfide motif from the bark of Eucommia ulmoides Oliv
Ren-Huai Huang, Ye Xiang, Xiao-Zhu Liu, Ying Zhang, Zhong Hu, Da-Cheng Wang FEBS Lett. 2002 Jun 19;521(1-3):87-90. doi: 10.1016/s0014-5793(02)02829-6.
Two antifungal peptides, named EAFP1 and EAFP2, have been purified from the bark of Eucommia ulmoides Oliv. Each of the sequences consists of 41 residues with a N-terminal blockage by pyroglutamic acid determined by automated Edman degradation in combination with the tandem mass spectroscopy and the C-terminal ladder sequencing analysis. The primary structurs all contain 10 cysteines, which are cross-linked to form five disulfide bridges with a pairing pattern (C1-C5, C2-C9, C3-C6, C4-C7, C8-C10). This is the first finding of a plant antifungal peptide with a five-disulfide motif. EAFP1 and EAFP2 show characteristics of hevein domain and exhibit chitin-binding properties similar to the previously identified hevein-like peptides. They exhibit relatively broad spectra of antifungal activities against eight pathogenic fungi from cotton, wheat, potato, tomato and tobacco. The inhibition activity of EAFP1 and EAFP2 can be effective on both chitin-containing and chitin-free fungi. The values of IC(50) range from 35 to 155 microg/ml for EAFP1 and 18 to 109 microg/ml for EAFP2. Their antifungal effects are strongly antagonized by calcium ions.
2. Mass spectrometric strategy for primary structure determination of N-terminally blocked peptides
Ren-Huai Huang, Da-Cheng Wang J Chromatogr B Analyt Technol Biomed Life Sci. 2004 Apr 15;803(1):167-72. doi: 10.1016/j.jchromb.2003.07.012.
The mass spectrometric strategy including three steps is presented for primary structure determination of the N-terminally blocked peptides. First, the C-terminal sequencing is performed by using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry coupled with carboxypeptidase Y digestion. Then, the peptide is cleaved according to the obtained C-terminal sequence information and the resulting peptides are identified by mass spectrometry and Edman degradation after fractionation by reverse-phase chromatography. Finally, the N-terminal fragment is sequenced by tandem mass spectrometry. The strategy was successfully applied to the sequence determination of two novel N-terminally blocked peptides named EAFP1 and EAFP2.
3. Crystallization and preliminary crystallographic studies of a novel antifungal protein with five disulfide bridges from Eucommia ulmoides Oliver
Ye Xiang, Ren-Huai Huang, Wei Liu, Gen-Pei Li, Xiao-Zhu Liu, Da-Cheng Wang Acta Crystallogr D Biol Crystallogr. 2002 Oct;58(Pt 10 Pt 2):1838-40. doi: 10.1107/s0907444902012131.
Two antifungal proteins, named Eucommia antifungal peptides 1 and 2 (EAFP1 and EAFP2), have been purified from the bark of the tree E. ulmoides Oliver and show a relatively broad spectrum of antifungal activity against several agriculturally important plant pathogens. One of these small proteins (EAFP2) has been crystallized. The crystal belongs to space group P2(1), with unit-cell parameters a = 19.01, b = 23.16, c = 30.69 A, beta = 98.54 degrees. 1.0 A resolution data were collected from an EAFP2 crystal and have been used to obtain phase information directly by an ab initio method.
