Simple modifications of the serpin reactive site loop convert SCCA2 into a cysteine proteinase inhibitor: A critical role for the P3 ' proline in facilitating RSL cleavage

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dc.contributor.author Luke, C.
dc.contributor.author Schick, C.
dc.contributor.author Tsu, C.
dc.contributor.author Whisstock, J. C.
dc.contributor.author Irving, J. A.
dc.contributor.author Bromme, D.
dc.contributor.author Juliano, L.
dc.contributor.author Shi, G. P.
dc.contributor.author Chapman, H. A.
dc.contributor.author Silverman, G. A.
dc.date.accessioned 2016-01-24T12:31:06Z
dc.date.available 2016-01-24T12:31:06Z
dc.date.issued 2000-06-20
dc.identifier http://dx.doi.org/10.1021/bi000050g
dc.identifier.citation Biochemistry. Washington: Amer Chemical Soc, v. 39, n. 24, p. 7081-7091, 2000.
dc.identifier.issn 0006-2960
dc.identifier.uri http://repositorio.unifesp.br/handle/11600/26328
dc.description.abstract The human squamous cell carcinoma antigens (SCCA) 1 and 2 are members of the serpin family that are 92% identical in their amino acid sequence. Despite this similarity, they inhibit distinct classes of proteinases. SCCA1 neutralizes the papain-like cysteine proteinases, cathepsins (cat) S, L, and K; and SCCA2 inhibits the chymotrypsin-like serine proteinases, catG and human mast cell chymase. SCCA2 also can inhibit catS, as well as other papain-like cysteine proteinases, albeit at a rate 50-fold less than that of SCCA1. Analysis of the mechanism of inhibition by SCCA1 revealed that the reactive site loop (RSL) is important for cysteine proteinase inhibition. the inhibition of catS by a mutant SCCA2 containing the RSL of SCCA1 is comparable to that of wild-type SCCA1. This finding suggested that there were no motifs outside and only eight residues within the RSL that were directing catS-specific inhibition. the purpose of this study was to determine which of these residues might account for the marked difference in the ability of SCCA 1 and SCCA2 to inhibit papain-like cysteine proteinases. SCCA2 molecules containing different RSL mutations showed that no single amino acid substitution could convert SCCA2 into a more potent cysteine proteinase inhibitor. Rather, different combinations of mutations led to incremental increases in catS inhibitory activity with residues in four positions (P1, P3', P4', and P11') accounting for 80% of the difference in activity between SCCA1 and SCCA2. Interestingly, the RSL cleavage site differed between wild-type SCCA2 and this mutant. Moreover, these data established the importance of a Pro residue in the P3' position for efficient inhibition of catS by both wild-type SCCA1 and mutated SCCA2. Molecular modeling studies suggested that this residue might facilitate positioning of the RSL within the active site of the cysteine proteinase. en
dc.format.extent 7081-7091
dc.language.iso eng
dc.publisher Amer Chemical Soc
dc.relation.ispartof Biochemistry
dc.rights Acesso restrito
dc.title Simple modifications of the serpin reactive site loop convert SCCA2 into a cysteine proteinase inhibitor: A critical role for the P3 ' proline in facilitating RSL cleavage en
dc.type Artigo
dc.contributor.institution Childrens Hosp
dc.contributor.institution Harvard Univ
dc.contributor.institution Monash Univ
dc.contributor.institution CUNY Mt Sinai Sch Med
dc.contributor.institution Universidade Federal de São Paulo (UNIFESP)
dc.description.affiliation Childrens Hosp, Div Newborn Med, Boston, MA 02115 USA
dc.description.affiliation Harvard Univ, Sch Med, Dept Pediat, Boston, MA 02115 USA
dc.description.affiliation Monash Univ, Dept Biochem & Mol Biol, Melbourne, Vic 3004, Australia
dc.description.affiliation CUNY Mt Sinai Sch Med, Dept Human Genet, New York, NY 10029 USA
dc.description.affiliation Universidade Federal de São Paulo, Dept Biophys, BR-04044 São Paulo, Brazil
dc.description.affiliation Harvard Univ, Sch Med, Brigham & Womens Hosp, Dept Med, Boston, MA 02115 USA
dc.description.affiliationUnifesp Universidade Federal de São Paulo, Dept Biophys, BR-04044 São Paulo, Brazil
dc.identifier.doi 10.1021/bi000050g
dc.description.source Web of Science
dc.identifier.wos WOS:000087778300006



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