d-aspartate oxidase (DDO) catalyzes the oxidative deamination of acidic d-amino acids, and its production is induced by d-Asp in several eukaryotes. The yeast Cryptococcus humicola strain UJ1 produces large amounts of DDO (ChDDO) only in the presence of d-Asp. In this study, we analyzed the relationship between d-Asp uptake by an amino acid permease (Aap) and the inducible expression of ChDDO. We identified two acidic Aap homologs, named “ChAap4 and ChAap5,” in the yeast genome sequence. ChAAP4 deletion resulted in partial growth defects on d-Asp as well as l-Asp, l-Glu, and l-Phe at pH 7, whereas ChAAP5 deletion caused partial growth defects on l-Phe and l-Lys, suggesting that ChAap4 might participate in d-Asp uptake as an acidic Aap. Interestingly, the growth of the Chaap4 strain on d- or l-Asp was completely abolished at pH 10, suggesting that ChAap4 is the only Aap responsible for d- and l-Asp uptake under high alkaline conditions. In addition, ChAAP4 deletion significantly decreased the induction of DDO activity and ChDDO transcription in the presence of d-Asp. This study revealed that d-Asp uptake by ChAap4 might be involved in the induction of ChDDO expression by d-Asp.

中文翻译：

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酵母隐球菌中d-天冬氨酸摄取的酸性氨基酸通透酶的鉴定

d-天冬氨酸氧化酶（DDO）催化酸性d-氨基酸的氧化脱氨作用，其产生是由几种真核生物中的d- Asp诱导的。仅在d- Asp存在下，酵母隐球菌UJ1菌株产生大量的DDO（ChDDO）。在这项研究中，我们分析了氨基酸渗透酶（Aap）吸收d- Asp与ChDDO的诱导表达之间的关系。我们在酵母基因组序列中鉴定了两个酸性Aap同源物，分别称为“ ChAap4和ChAap5”。ChAAP4缺失导致偏生长缺陷D-天冬氨酸以及1-天冬氨酸，1-谷氨酸，和1-苯丙氨酸在pH 7，而ChAAP5删除引起的偏生长缺陷1- Phe和1-赖氨酸，这表明ChAap4可能参与D-天冬氨酸摄取作为酸性AAP。有趣的是，生长Chaap4应变D-或1-天冬氨酸在pH 10完全消失，这表明ChAap4是唯一的AAP负责D-和1-高碱性条件下的Asp摄取。另外，在d- Asp存在下，ChAAP4缺失显着降低了DDO活性的诱导和ChDDO转录。这项研究表明ChAap4吸收d- Asp可能与d- Asp诱导ChDDO表达有关。