Toward the Construction of a Kinetic Model of Methionine and Thereonine Biosynthesis to Increase Seed Nutritional Value: Characterization of Threonine Synthase.

胱硫醚β合酶 生物化学 苏氨酸 生物合成 蛋氨酸 生物 氨基酸 ATP合酶 变构调节 代谢工程 丝氨酸
作者
Dominique Morneau
标识
DOI:10.22215/etd/2014-10319
摘要

Improving the nutritional quality of crop species, like Cicer arietinum and Lens culinaris, is of particular interest to agricultural biotechnology.These crops are deficient, from a human dietary perspective, in the essential amino acid L-methionine (L-Met).In plants, the biosynthesis of L-Met is initiated by the formation of L-cystathionine from Ophospho-L-homoserine (OPHS) catalyzed by cystathionine γ-synthase (CGS).OPHS occupies the branch-point between L-Met and L-threonine (L-Thr) biosynthesis, catalyzed by threonine synthase (TS), making these two enzymes targets for metabolic engineering studies to increase L-Met production.The construction of a kinetic model recreating the branch-point can facilitate the metabolic engineering of important crop species by providing a tool for anticipating disturbances in metabolic flux caused by manipulations to the branch-point.The focus of the research described in this thesis is to provide a starting point for the creation of a kinetic model of the OPHS branch-point in the target species.The characterization of plant TS requires a continuous spectrophotometric assay, which was developed using a non-allosteric variant of threonine deaminase from Escherichia coli (eTD L447F ) and hydroxyisocaproate dehydrogenase (HO-HxoDH) from Lactobacillus delbrueckii.The assay was verified for suitability for use under the various pH optima of TS across phyla.The functional coding sequences of TS from C. arietinum (CaTS) and L. culinaris (LcTS) share approximately 80% amino acid sequence identity with TS from Glycine max, and the residues of the allosteric site are conserved with those of TS from other plant species.The PLP-binding motif, which is conserved across plant and microbial species, is present in the active site of both enzymes.The kinetic parameters of CaTS, LcTS, and AtTS2 were measured with 100 µM of the iii allosteric activator S-adenosyl-L-methionine (SAM), with the parameters of AtTS1 measured as a control.SAM increases the k cat /K m OPHS of AtTS2, LcTS, CaTS, and AtTS1 by 10-, 20-, 25-, and 80-fold, respectively.Due to the varying flux control patterns of TS from A. thaliana, C. arietinum, and L. culinaris, the construction of a species-specific kinetic model of the branch-point is needed for future aimed at increasing L-Met biosynthesis to nutritionally significant levels.
最长约 10秒,即可获得该文献文件

科研通智能强力驱动
Strongly Powered by AbleSci AI
更新
PDF的下载单位、IP信息已删除 (2025-6-4)

科研通是完全免费的文献互助平台,具备全网最快的应助速度,最高的求助完成率。 对每一个文献求助,科研通都将尽心尽力,给求助人一个满意的交代。
实时播报
刚刚
2秒前
2秒前
heiztcasino发布了新的文献求助10
2秒前
量子星尘发布了新的文献求助10
3秒前
3秒前
4秒前
小蚊子发布了新的文献求助10
4秒前
qiaoj2006完成签到,获得积分10
4秒前
许欣瑞完成签到,获得积分10
4秒前
CipherSage应助ldy采纳,获得10
4秒前
tectextey发布了新的文献求助10
5秒前
万能图书馆应助KYTQQ采纳,获得20
6秒前
保住头发为科研完成签到,获得积分10
7秒前
田様应助北纬打工人采纳,获得10
7秒前
科目三应助无心的青槐采纳,获得20
7秒前
heiztcasino完成签到,获得积分10
7秒前
大个应助科研通管家采纳,获得10
8秒前
彭于晏应助晚霞常有遗憾采纳,获得10
8秒前
李爱国应助科研通管家采纳,获得10
8秒前
科研通AI6应助科研通管家采纳,获得10
8秒前
攀攀发布了新的文献求助10
8秒前
领导范儿应助科研通管家采纳,获得10
8秒前
共享精神应助科研通管家采纳,获得10
8秒前
科研通AI6应助科研通管家采纳,获得10
8秒前
blackbody发布了新的文献求助30
8秒前
小二郎应助科研通管家采纳,获得10
8秒前
隐形曼青应助科研通管家采纳,获得10
8秒前
大模型应助科研通管家采纳,获得10
8秒前
淡淡朝阳发布了新的文献求助20
8秒前
赘婿应助科研通管家采纳,获得10
8秒前
暖暖关注了科研通微信公众号
8秒前
华仔应助科研通管家采纳,获得10
8秒前
wuchang完成签到 ,获得积分10
8秒前
聪慧小霜应助科研通管家采纳,获得10
8秒前
Orange应助科研通管家采纳,获得10
9秒前
科研通AI2S应助科研通管家采纳,获得10
9秒前
彭于晏应助科研通管家采纳,获得20
9秒前
CipherSage应助qiongqiong采纳,获得10
9秒前
领导范儿应助科研通管家采纳,获得10
9秒前
高分求助中
(应助此贴封号)【重要!!请各用户(尤其是新用户)详细阅读】【科研通的精品贴汇总】 10000
计划经济时代的工厂管理与工人状况(1949-1966)——以郑州市国营工厂为例 500
INQUIRY-BASED PEDAGOGY TO SUPPORT STEM LEARNING AND 21ST CENTURY SKILLS: PREPARING NEW TEACHERS TO IMPLEMENT PROJECT AND PROBLEM-BASED LEARNING 500
The Pedagogical Leadership in the Early Years (PLEY) Quality Rating Scale 410
Stackable Smart Footwear Rack Using Infrared Sensor 300
Modern Britain, 1750 to the Present (第2版) 300
Writing to the Rhythm of Labor Cultural Politics of the Chinese Revolution, 1942–1976 300
热门求助领域 (近24小时)
化学 材料科学 医学 生物 工程类 有机化学 生物化学 物理 纳米技术 计算机科学 内科学 化学工程 复合材料 物理化学 基因 催化作用 遗传学 冶金 电极 光电子学
热门帖子
关注 科研通微信公众号,转发送积分 4603484
求助须知:如何正确求助?哪些是违规求助? 4012177
关于积分的说明 12422449
捐赠科研通 3692673
什么是DOI,文献DOI怎么找? 2035749
邀请新用户注册赠送积分活动 1068916
科研通“疑难数据库(出版商)”最低求助积分说明 953403