| 词条 | Threonine protease | |||||||||
| 释义 |
| Symbol = Thr | Name = Threonine Protease | image = Protein_PSMA1_PDB_1iru.png | image_source = PDB rendering based on 1iru. | PDB = {{PDB2|1iru}} | width = | caption = Crystal structure of human proteasome alpha 1 | Pfam= | Pfam_clan = | InterPro = | SMART = | PROSITE = | MEROPS = | SCOP = | TCDB = | OPM family = | OPM protein = }} Threonine proteases are a family of proteolytic enzymes harbouring a threonine (Thr) residue within the active site. The prototype members of this class of enzymes are the catalytic subunits of the proteasome, however the acyltransferases convergently evolved the same active site geometry and mechanism. Mechanism{{see also|catalytic triad}}Threonine proteases use the secondary alcohol of their N-terminal threonine as a nucleophile to perform catalysis.[1][2] The threonine must be N-terminal since the terminal amine of the same residue acts as a general base by polarising an ordered water which deprotonates the alcohol to increase its reactivity as a nucleophile.[3][4] Catalysis takes place in two steps:
Classification and evolution{{see also|catalytic triad}}Five families belonging to two separate superfamilies are currently recognised: the Ntn fold proteosomes[1] (superfamily PB) and the DOM fold ornithine acyltransferases[2] (superfamily PE). The two superfamilies represent two independent, convergent evolutions of the same active site.[4][5]
See also{{colbegin}}
References1. ^1 {{cite journal | vauthors = Brannigan JA, Dodson G, Duggleby HJ, Moody PC, Smith JL, Tomchick DR, Murzin AG | title = A protein catalytic framework with an N-terminal nucleophile is capable of self-activation | journal = Nature | volume = 378 | issue = 6555 | pages = 416–9 | date = November 1995 | pmid = 7477383 | doi = 10.1038/378416a0 }} {{Proteases}}{{Enzymes}}{{Portal bar|Molecular and Cellular Biology|border=no}}2. ^1 {{cite journal | vauthors = Cheng H, Grishin NV | title = DOM-fold: a structure with crossing loops found in DmpA, ornithine acetyltransferase, and molybdenum cofactor-binding domain | journal = Protein Science | volume = 14 | issue = 7 | pages = 1902–10 | date = July 2005 | pmid = 15937278 | pmc = 2253344 | doi = 10.1110/ps.051364905 }} 3. ^{{cite journal | vauthors = Dodson G, Wlodawer A | title = Catalytic triads and their relatives | journal = Trends in Biochemical Sciences | volume = 23 | issue = 9 | pages = 347–52 | date = September 1998 | pmid = 9787641 | doi = 10.1016/S0968-0004(98)01254-7 }} 4. ^1 {{cite journal | vauthors = Ekici OD, Paetzel M, Dalbey RE | title = Unconventional serine proteases: variations on the catalytic Ser/His/Asp triad configuration | journal = Protein Science | volume = 17 | issue = 12 | pages = 2023–37 | date = December 2008 | pmid = 18824507 | pmc = 2590910 | doi = 10.1110/ps.035436.108 }} 5. ^{{cite journal | vauthors = Buller AR, Townsend CA | title = Intrinsic evolutionary constraints on protease structure, enzyme acylation, and the identity of the catalytic triad | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 110 | issue = 8 | pages = E653-61 | date = February 2013 | pmid = 23382230 | pmc = 3581919 | doi = 10.1073/pnas.1221050110 }} 2 : Peptidase|EC 3.4 |
|||||||||
| 随便看 |
|
开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。