排序方式: 共有5条查询结果,搜索用时 12 毫秒
1
1.
Bukhari Muhammad Adnan Ahmad Zahoor Ashraf M. Yasin Afzal Muhammad Nawaz Fahim Nafees Muhammad Jatoi Wajid Nasim Malghani Naveed Aslam Shah Adnan Noor Manan Abdul 《SILICON》2021,13(12):4757-4772
Silicon - Feeling prone to stress differs with plant production stage, water scarcity near commencement of grain filling phase has a significant reduced grain yield through fewer endosperm and sink... 相似文献
2.
Cheley S; Malghani MS; Song L; Hobaugh M; Gouaux JE; Yang J; Bayley H 《Protein engineering, design & selection : PEDS》1997,10(12):1433-1443
Staphylococcal alpha-hemolysin is a water soluble, monomeric, bacterial
exotoxin, which forms heptameric pores in membranes. The rate determining
step in assembly is the conversion of a heptameric prepore to the fully
assembled pore in which the central glycine-rich domain of each subunit
inserts into the membrane to form a 14 strand beta barrel. Barrel formation
is accompanied by a conformational change in which each N terminus latches
onto an adjacent subunit. In the monomer in solution, the central domain is
loosely organized and exposed to solvent. In this study, 25 amino acids of
the central domain were removed and replaced with the sequence Asp-Gly,
which favors the formation of a type I' beta-turn, to yield a mutant devoid
of hemolytic activity. Within minutes after synthesis in the absence of
membranes, the mutant polypeptide spontaneously assembled into heptamers,
as demonstrated by atomic force microscopy. Limited proteolysis suggested
that the N termini of the subunits in the heptamers were in the fully
assembled pore conformation rather than the prepore conformation. Based on
these findings, the deletion is proposed to constrain the central domain
and thereby force the creation of a shortened beta barrel, which in turn
induces the additional structural changes that normally accompany pore
formation. The truncated pore might make a useful framework for the
construction of designed membrane active macromolecules.
相似文献
3.
M. S. Malghani R. M. Lees J. W. C. Johns 《Journal of Infrared, Millimeter and Terahertz Waves》1987,8(8):803-825
The far-infrared (FIR) spectrum of CH3NH2 has been studied in the 25–125 cm?1 region at a resolution of 0.005 cm?1 with a BOMEM Fourier transform spectrometer. All of therR branches with K rotational quantum number from 5 to 13 have been identified for A-a and E-a torsion-inversion symmetries in the ground torsional state, as well as some branches of A-s and E-s symmetries and some in excited torsional states. The observed branches have been fitted to series expansions in order to determine the branch origins. 相似文献
4.
5.
Atomic force microscopy has been used to study self-assembled structures of two alpha-hemolysin mutants. For a mutant (alphaHL-H5) that was locked into the prepore state on fluid phase egg-PC membranes, we visualized, for the first time, heptameric prepores and showed that the 7-fold axis in the prepore lies perpendicular to the membrane surface. For another mutant (TCM) with the transmembrane domain, the self-assembled oligomer that assumes the conformation of the fully assembled pore is also a heptamer. These results show that heptamers are the preferred oligomerization state of alpha-hemolysin. 相似文献
1