Publications

Authors:

Cellini, Barbara; Montioli, Riccardo; Bossi, Alessandra Maria; Bertoldi, Mariarita; Laurents, Dv; Voltattorni, Carla

Title:

Holo-and apocystalysin from Treponema denticola: two different conformations

Year:

2006

Type of item:

Articolo in Rivista

Tipologia ANVUR:

Articolo su rivista

Language:

Inglese

Referee:

Sì

Name of journal:

Archives of Biochemistry and Biophysics

ISSN of journal:

0003-9861

N° Volume:

455

:

Elsevier Science

Page numbers:

31-39

Keyword:

Cystalysin, Isoelectric point, Limited proteolysis, Pyridoxal 5′-phosphate

Short description of contents:

Cystalysin, the key virulence factor in the bacterium Treponema denticola responsible for periodontis, is a pyridoxal 5′-phosphate (PLP) enzyme which catalyzes, in addition to α,β-elimination of l-cysteine, racemization and transamination of both enantiomers of alanine. In this paper several indicators have been used as probes of the different conformational status of T. denticola cystalysin in the holo and apo form. Compared to holoenzyme, the apoenzyme displays an altered reactivity of cysteine residues, a significantly different pI, and a differential susceptibility to proteinase K. The site of cleavage that is accessible in apocystalysin and masked in holocystalysin has been identified by mass spectrometry as the peptide bond between Phe 360 and Gly 361. This cleavage results in the loss of the C-terminal fragment corresponding to a molecular mass of 4289.21 ± 0.1 Da. The major fragment of cleaved enzyme retains its dimeric structure, binds the coenzyme with an affinity ∼5000-fold lower than that of uncleaved holoenzyme, and in the reconstituted form is able to form the external aldimine with substrates. Although the break causes the loss of lyase, racemase and transaminase activities of d-alanine, it does not abolish the transaminase activity of l-alanine. Possible mechanistic and physiological implications are proposed. © 2006 Elsevier Inc. All rights reserved.

Product ID:

36859

Handle IRIS:

11562/305414

Deposited On:

July 18, 2007

Last Modified:

December 1, 2022

Bibliographic citation:

Cellini, Barbara; Montioli, Riccardo; Bossi, Alessandra Maria; Bertoldi, Mariarita; Laurents, Dv; Voltattorni, Carla, Holo-and apocystalysin from Treponema denticola: two different conformations «Archives of Biochemistry and Biophysics» , vol. 455 , 2006 , pp. 31-39

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