ubiquitin

(redirected from Ubiquitins)
Also found in: Dictionary, Encyclopedia.

u·biq·ui·tin

(ū-bik'kwi-tin), [MIM*191320]
A small (76 amino acyl residues) protein found in all cells of higher organisms and one with a structure that has changed minimally during evolutionary history; involved in at least two processes; histone modification and intracellular protein breakdown.

ubiquitin

(yo͞o-bĭk′wĭ-tĭn)
n.
A small protein found in all eukaryotic cells that attaches to other proteins, thereby regulating their activity or location or marking them for degradation.

ubiquitin

[yo̅o̅bik′witin]
a small polypeptide that is involved in histone modification and is a marker for intracellular protein transport and breakdown. It is found in all cells of higher organisms.

u·bi·qui·tin

(yū-bik'kwi-tin)
A small protein found in all cells of higher organisms; its structure has changed minimally during evolutionary history; involved in histone modification and intracellular protein breakdown.

ubiquitin

A small 76-residue protein found in all animal cells and known to have altered minimally throughout evolutionary history. Ubiquitin is linked by covalent bonds to proteins destined for destruction by PROTEASOMES.

ubiquitin

a small PROTEIN, present in all eukaryotic cells (ubiquitous protein), containing a highly conserved sequence of 76 AMINO ACIDS, that is identical in a wide range of organisms including humans, fish and insects. Ubiquitin is involved in a number of cellular functions, such as protein degradation and modifications to CHROMATIN structure.

ubiquitin (yōōˈ·biˑ·kwi·tin),

n a 76-amino acid polypeptide from modification of histones; present in yeast and in most eukaryotic cells.

ubiquitin

heat shock (cell stress) protein present in mammalian cytosol; attaches to other cytosolic proteins and marks them for degradation either by specific proteases or by lysosomal enzymes.
References in periodicals archive ?
The x ray structure of ubiquitin (PDB accession code 1UBQ) (30) was placed in a box of TIP3 water molecules (31) the dimensions of which depended on the geometry of the pulling process: 1) for stretching from the C- and the N-terminis 68.
Stretching ubiquitin between the C- and the N- termini: PNW was applied by fixing the C[alpha] of the C-terminus and applying a harmonic potential (elastic constant of 3 kcal /mol [[Angstrom].
Stretching ubiquitin between C-terminus and Lys48: The C[alpha] of Lys 48 was fixed and the C[alpha] of the C terminus was pulled with an external force (elastic constant of 2 kcal/mol [Angstrom]2) along the C[alpha] to C[alpha] direction (Figure 6), using one hundred ps of simulation and 2 [Angstrom] of extension per step.
Stretching ubiquitin between its N-terminus and Lys63: PNW simulations were also implemented by fixing the C[alpha] of Lys 63 and pulling the C[alpha] of the N-terminus (Figure 9).
AFM studies of ubiquitin have exploited its unusual ability to form homopolyproteins in which stretching forces can be transmitted to various segments of the monomer via different linkages (different attachment points).
In summary, by using a simulation protocol that allows equilibration at each extension (PNW protocol) we have been able to observe the details of the events leading to the unfolding of ubiquitin by mechanical force.
The mechanical stability of ubiquitin is linkage dependent, Nat Struct Biol2003; 10 (9): 738-743.
Reversible mechanical unfolding of single ubiquitin molecules, Biophys J 2004; 87 (6): 3995-4006.

Full browser ?