Site-directed mutagenesis of two aromatic residues lining the active site pocket of the yeast Ltp1.
Site-directed mutagenesis of two aromatic residues lining the active site pocket of the yeast Ltp1.
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对酵母 Ltp1 活性位点袋内的两个芳香族残基进行定点诱变。
DOI：
10.1016/j.bbagen.2006.12.012
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
G. Ramponi
中科院分区：
文献类型：
--
作者：
P. Paoli;A. Modesti;F. Magherini;T. Gamberi;Anna Caselli;G. Manao;G. Raugei;G. Camici;G. Ramponi
We mutated Trp134and Tyr135of the yeast LMW-PTP to explore their catalytic roles, demonstrating that the mutations of Trp134to Tyr or Ala, and Tyr135to Ala, all interfere with the formation of the phosphorylenzyme intermediate, a phenomenon that can be seen by the decrease in the kinetic constant of the chemical step (k3). Furthermore, we noted that the Trp134to Ala mutation causes a dramatic drop in kcat/Kmand a slight enhancement of the dissociation constant Ks. The conservative mutant W134Y shows a kcat/Kmvery close to that of wild type, probably compensating the two-fold decrease of k3with an increase in substrate affinity. The Y135A mutation enhances the substrate affinity, but reduces the enzyme phosphorylation rate. The replacement of Trp134with alanine interferes with the partition between phosphorylenzyme hydrolysis and phosphotransfer from the phosphorylenzyme to glycerol and abolish the enzyme activation by adenine. Finally, we found that mutation of Trp134to Ala causes a dramatic change in the pH-rate profile that becomes similar to that of the D132A mutant, suggesting that an aromatic residue in position 134 is necessary to assist the proper positioning of the proton donor in the transition state of the chemical step.
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影响因子：
2.9
作者：
Juszczak, LJ;Zhang, ZY;Eads, DD
通讯作者：
Eads, DD
DOI：
10.1016/s0021-9258(18)52325-5
发表时间：
1991-01
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Zhong Yin Zhang;R. L. Vanetten
通讯作者：
Zhong Yin Zhang;R. L. Vanetten
腺嘌呤激活低分子量蛋白酪氨酸磷酸酶的结构和机制基础。
影响因子：
2.9
作者：
Wang,S;Stauffacher,CV;VanEtten,RL
通讯作者：
VanEtten,RL
影响因子：
2.9
作者：
SANTORO, MM;BOLEN, DW
通讯作者：
BOLEN, DW
影响因子：
2.9
作者：
Wang, SS;Tabernero, L;Stauffacher, CV
通讯作者：
Stauffacher, CV