Papain three-dimensional structure

CBH II 447 ABB -core aa sequence in part from protein and in full from gene (cbh2), number of SS bridges, region of O-glycosylation, types of carbohydrate, papain cleavage site, hydrophobic cluster analysis, SAXS on whole CBH II and head domain, three dimensional structure of head by X-ray diffraction... 

Hie amino acid sequence of papain was determined in 1970 by Mitchel et al. [15] (Fig. 1). It exists as an unglycosylaled polypeptide of Mr 23406 (212 amino acid residues). Papain was the first cysteine proteinase for which the three-dimensional structure was deduced from x-ray diffraction data. The... 

Jacquct et al. described the proteolytic specificities of chymopapain and papaya proteinase Q [36]. The polypeptide chain of caricain contains 216 amino acid residues (Mr 23283). The molecule shares 148 identical amino acid residues (68,5ft) with papain. 141 with chymopapain (65,2ft), and 175 with glycyl endopeptidase (81.0ft). The Ms,lllOnin is 1U [20]. The three-dimensional structure of caricain has been determined by x-ray diffraction analysis [37,38]-... 

The amino add sequence of glycyl endopeptidase was published by Ritonja et al. [45] (Fig. 1). The enzyme exists as a single unglycosylated polypeptide of 216 amino add residues (Mr 23.313). Glycyl endopeptidase is clearly a member of the papain family of cysteine proteinases [46], The three-dimensional structure... 

Examination of the three-dimensional structure of papain (Lab Quip) indicated that because of the extended groove present in the vicinity of the active site residue Cys-25, it should be feasible to alkylate the sulfhydryl group with a coenzyme analog, still permitting the binding of potential substrates. 

Internal water molecules may be located in the same sites in related proteins. In many proteins, internal waters are an essential part of the three-dimensional structure and their positions are typical for a whole family of proteins. Thus, in the three related plant cysteine proteinases, actinidin, papain, and calotropin Dl, 15 of the 16 internal waters (8 of which are illustrated in Fig. 19.13) are found in... 

In 1988, Looze et al. published a series of articles on the cysteine proteinases from papaya latex. In the first article, they described an alternative way to purify chymopapain and papaya proteinase Q to homogeneity [32], In the following articles the primary structures of chymopapain [33] and papaya proteinase 12 [34] were described (Fig. 1). The primary structure of chymopapain determined by Watson et al. [35] is in perfect agreement with the results of Dubois et al. Jacquet et al. described the proteolytic specificities of chymopapain and papaya proteinase 12 [36]. The polypeptide chain of caricain contains 216 amino acid residues (Mr 23283). The molecule shares 148 identical amino acid residues (68.5%) with papain, 141 with chymopapain (65.2%), and 175 with glycyl endo-peptidase (81.0%). The Ai%,280nm is 18.3 [20]. The three-dimensional structure of caricain has been determined by x-ray diffraction analysis [37,38]. 

The three-dimensional structure of many enzyme molecules, including hydrolytic enzymes such as lysozyme, chymotrypsin, ribonuclease, carboxypeptidase A, elastase, and papain, has been determined in recent years throu] the X-ray diffraction method, and the steric arrangement and function of amino acid residues at the active site has been elucidated (/). 

Papain, EC 3.4.22.2, the archetype of cysteine peptidases. It was isolated from the latex of the tropical papaya fruit (Carica papaya). Papain is a single-chain protein (212 aa 23 kDa) containing three disulfide bonds and a known three-dimensional structure with 1.65 A resolution The catalytic amino acid residues have been identified as Cys, His and Asn, whereas Gln helps to stabilize the oxyanion hole. Papain has a fairly broad specificity [J. R. Kimmel, E. L. Smith, J. Biol. Chem. 1954, 207, 515 A. C. Storer, R. Menard, Methods Enzymol. 1994, 244, 486]. 

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