Biomaterial Database

In vitro analysis of microtubule assembly of isotypically pure tubulin dimers. Intrinsic differences in the assembly properties of alpha beta II, alpha beta III, and alpha beta IV tubulin dimers in the absence of microtubule-associated proteins. 1994

Q Lu, and R F Luduena

Department of Biochemistry, University of Texas Health Science Center, San Antonio 78284-7760.

Microtubule assembly of different beta tubulin isotypes in the presence of 4 M glycerol and 6 mM magnesium ion demonstrates significantly different characteristics. alpha beta II and alpha beta IV assembled faster and to a greater extent than did unfractionated phosphocellulose-purified tubulin (PC-tubulin). Microtubule assembly from alpha beta III showed a distinctive delay in nucleation, proceeded at a slower rate than those of the other beta tubulin isotypes, and had the highest critical concentration. However, treatment of beta tubulin isotypes with subtilisin to remove the C-terminal domain of the tubulin dimer abolished these differences in microtubule assembly pattern and enhanced self-assembly. The kinetic analysis of microtubule elongation of different beta tubulin isotypes also showed significant differences. Elongation of alpha beta III from microtubule seeds had a lower apparent K alpha and a lower apparent Kd than did alpha beta II and alpha beta IV. The dynamic behaviors of different beta tubulin isotypes were qualitatively similar to each other and fit the dynamic instability model. However, microtubules formed from alpha beta III appeared to be less dynamic than microtubules formed from other beta tubulin isotypes. Our results suggest that the beta III isotype might have a different conformation than do the other beta tubulin isotypes. The distinctive nucleation and elongation behaviors of the alpha beta III dimers demonstrated in vitro may have a significant influence on microtubule functions in vivo.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008274	Magnesium	A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D008870	Microtubules	Slender, cylindrical filaments found in the cytoskeleton of plant and animal cells. They are composed of the protein TUBULIN and are influenced by TUBULIN MODULATORS.	Microtubule
D010446	Peptide Fragments	Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.	Peptide Fragment,Fragment, Peptide,Fragments, Peptide
D001921	Brain	The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.	Encephalon
D002417	Cattle	Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.	Beef Cow,Bos grunniens,Bos indicus,Bos indicus Cattle,Bos taurus,Cow,Cow, Domestic,Dairy Cow,Holstein Cow,Indicine Cattle,Taurine Cattle,Taurus Cattle,Yak,Zebu,Beef Cows,Bos indicus Cattles,Cattle, Bos indicus,Cattle, Indicine,Cattle, Taurine,Cattle, Taurus,Cattles, Bos indicus,Cattles, Indicine,Cattles, Taurine,Cattles, Taurus,Cow, Beef,Cow, Dairy,Cow, Holstein,Cows,Dairy Cows,Domestic Cow,Domestic Cows,Indicine Cattles,Taurine Cattles,Taurus Cattles,Yaks,Zebus
D005990	Glycerol	A trihydroxy sugar alcohol that is an intermediate in carbohydrate and lipid metabolism. It is used as a solvent, emollient, pharmaceutical agent, or sweetening agent.	1,2,3-Propanetriol,Glycerin,1,2,3-Trihydroxypropane,Glycerine
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013381	Subtilisins	A family of SERINE ENDOPEPTIDASES isolated from Bacillus subtilis. EC 3.4.21.-	Alcalase,AprA-Subtilisin,Bacillus amyloliquefaciens Serine Protease,Bacillus subtilis Alkaline Proteinase,Carlsberg Subtilisin,Maxatase,Nagarse,Novo Alcalase,Profezim,Protease VII,Subtilisin 72,Subtilisin A,Subtilisin BPN',Subtilisin Carlsberg,Subtilisin DY,Subtilisin E,Subtilisin GX,Subtilisin Novo,Subtilopeptidase A,Alcalase, Novo,AprA Subtilisin,Subtilisin, Carlsberg