Physiological control of amonabactin biosynthesis in Aeromonas hydrophila.
Physiological control of amonabactin biosynthesis in Aeromonas hydrophila.
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DOI：
10.1007/bf01142554
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发表时间：
1989-01-01
期刊：
影响因子：
--
通讯作者：
Byers, B R
中科院分区：
文献类型：
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作者：
Barghouthi, S;Young, R;Byers, B R
Amonabactin是嗜水气单胞菌的铁载体，由2，3-二羟基苯甲酸(DHB)、赖氨酸、甘氨酸和酪氨酸(Amonabactin T)或苯丙氨酸(Amonabactin P)两种生物活性形式产生。在铬天青S铁载体检测琼脂上分离和鉴定了不产生氨基肌动蛋白或过量产生铁载体的氨基生物合成突变体(化学诱变产生)。Amonabactin阴性突变体分为两类。一种类型不产生酚类物质，并利用外源DHB合成氨基丁酸(两种形式)，而另一种类型分泌DHB，但不分泌氨基丁酸。这表明氨基肌动蛋白的生物合成途径由两个片段组成，一个产生DHB，另一个由DHB和氨基酸组装氨基肌动蛋白。产量过高的突变体使用氨基肌动蛋白的情况很差，或者根本不使用，这表明它们在氨基肌动蛋白的利用中存在损伤。将类似的D-色氨酸加入到野生型嗜水气单胞菌培养物中，减少了氨基肌动蛋白T和氨基肌动蛋白P的合成，并延长了铁限制培养基中的滞后期。色氨酸和苯丙氨酸形式的氨基结合蛋白可以通过含有一种新型酶(对D-色氨酸敏感)的单一组装途径来合成，该酶可以将色氨酸或苯丙氨酸插入氨基结合蛋白中。
Amonabactin is a siderophore from Aeromonas hydrophila which is produced in two biologically active forms composed of the phenolate 2,3-dihydroxybenzoic acid (DHB), lysine, glycine, and either trytophan (amonabactin T) or phenylalanine (amonabactin P). Amonabactin biosynthetic mutants (generated by chemical mutagenesis) that either produced no amonabactin or overproduced the siderophore were isolated and identified on chrome azurol S siderophore detection agar. Amonabactin-negative mutants were of two categories. One type produced no phenolates and used exogenous DHB to synthesize amonabactin (both forms) while the other type excreted DHB but not amonabactin. This suggests an amonabactin biosynthetic pathway composed of two segments, one producing DHB and the other assembling amonabactin from DHB and the amino acids. Overproduction mutants used amonabactin poorly or not at all, indicating that they contained lesions in amonabactin utilization. Adding the analog D-tryptophan to wild-type A. hydrophila cultures reduced synthesis of both amonabactin T and amonabactin P and lengthened the lag phase in iron restricted medium. The tryptophan and phenylalanine forms of amonabactin may be synthesized by a single assembly pathway that contains a novel enzyme (sensitive to D-tryptophan) which inserts either tryptophan or phenylalanine into amonabactin.