Candida albicans and Saccharomyces cerevisiae expressing ALA1/ALS5 adhere to accessible threonine, serine, or alanine patches
Candida albicans and Saccharomyces cerevisiae expressing ALA1/ALS5 adhere to accessible threonine, serine, or alanine patches
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DOI：
10.1080/15419060212187
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发表时间：
2002-01-01
影响因子：
--
通讯作者：
Klotz, SA
中科院分区：
文献类型：
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作者：
Gaur, NK;Smith, RL;Klotz, SA
用白色念珠菌 ALA1/ALS5 转化的酿酒酵母表现出与白色念珠菌相似的粘附特性。真菌与固定化蛋白质的粘附涉及氢键，对剪切力稳定，并且能够抵抗各种生物分子的竞争。 Ala1/Als5p 介导的粘附中靶标识别的特异性决定因素尚不清楚。为了确定焦油（尚未识别）的特征，将蛋白质和小肽在 N 末端共价偶联到羧酸盐修饰的磁珠表面。表达粘附素 Ala1/Als5p 的白色念珠菌酵母细胞、芽管和假菌丝和酿酒酵母粘附到涂有纤连蛋白、层粘连蛋白、IV 型胶原、牛血清白蛋白和酪蛋白的珠子上。未观察到对珠子的粘附然而，苏氨酸、丝氨酸和丙氨酸的 10 聚体均聚物充当粘附的配体。要实现最大粘附，还需要在肽中存在最少 4 个连续的苏氨酸残基。另一方面，在C末端具有少量苏氨酸和丝氨酸残基以及赖氨酸的胶原蛋白和纤连蛋白10聚体肽不能作为粘附配体，通过在C末端添加苏氨酸或丝氨酸残基或去除赖氨酸残基并在肽中的任何位置添加苏氨酸残基，它们都被转化为粘附配体。 C 末端可能导致肽在 N 末端和 C 末端偶联，从而使苏氨酸残基无法粘附，因此，Ala1/Als5p 识别某些氨基酸的片段，这些氨基酸在发生粘附之前必须是可接近的。
Saccharomyces cerevisiae transformed with Candida albicans ALA1/ALS5 exhibits adherence properties similar to C. albicans. Adherence of the fungi to immobilized proteins involves hydrogen bonds, is stable to shear forces, and is resistant to competition from various biological molecules. The specificity determinants of target recognition in Ala1/Als5p-mediated adherence are not known. To determine features of tar(yet recognition, proteins and small peptides were covalently coupled at the N-terminus to the surface of carboxylate-modified magnetic beads. C. albicans yeast cells, germ tubes and pseudohyphae and S. cerevisiae expressing the adhesin, Ala1/Als5p, adhered to beads coated with fibronectin, laminin, type IV collagen, bovine serum albumin, and casein. No adherence to beads was observed if a single amino acid was coupled to the beads. However, 10-mer homopolymers of threonine, serine, and alanine served as ligands for adherence. The presence of a minimum of four contiguous threonine residues in a peptide was required for maximal adherence. Coupling of 10-mer peptides from fibronectin and Ala1/Als5p each possessing 5-7 threonine or serine residues also initiated adherence. On the other hand, a collagen and a fibronectin 10-mer peptide with few threonine and serine residues and lysine at the C-terminus did not serve as adherence ligands. Both of them are converted to adherence ligands by adding threonine or serine residues at the C-terminus or removing the lysine residue and adding threonine residues anywhere in the peptide. The presence of lysine at the C-terminus may have resulted in coupling of the peptides at both the N- and C-termini, thus making the threonine residues inaccessible for adherence. Thus, Ala1/Als5p recognizes patches of certain amino acids, which must be accessible before adherence will occur.