Dataset Information

Primary structure and possible origin of the non-glycosylated basic proline-rich protein of human submandibular/sublingual saliva.

ABSTRACT: Human submandibular/sublingual saliva contains one non-glycosylated basic proline-rich protein whereas parotid saliva contains multiple such components. The submandibular protein has a primary structure identical with the C-terminal segment [TZ] of the human parotid acidic proline-rich proteins that contain 150 amino acid residues (Mr 16,000). Northern-blot analyses of human parotid and submandibular glands revealed that mRNAs containing the HaeIII repeat sequence typical for acidic proline-rich proteins are expressed in both of these salivary glands whereas mRNAs for non-glycosylated basic proline-rich proteins containing a typical BstN1 repeat sequence are expressed in the parotid but not in the submandibular gland. Products of translation in vitro of mRNAs from human parotid and submandibular glands were also examined. Two immunoprecipitable bands with Mr 29,000 and 28,000 were obtained by translation of both parotid and submandibular mRNA. In the presence of microsomal membranes these proteins gave rise to proteins electrophoretically identical with the secreted acidic proline-rich proteins of Mr 16,000. These proteins were cleaved by kallikrein, giving rise to proteins with electrophoretic mobilities identical with those of a smaller acidic proline-rich protein with Mr 11,000 and peptide TZ. Additional immunoprecipitable bands with Mr ranging from 35,000 to 46,000 were seen when parotid mRNA was used for translation in vitro, and are believed to be precursors of the basic proline-rich proteins encoded by the BstN1 repeat type mRNA. Neither these bands nor a separate precursor for the basic non-glycosylated proline-rich protein was detected when submandibular mRNA was used for translation in vitro. It is suggested that the non-glycosylated basic proline-rich protein present in human submandibular saliva arises by cleavage of acidic proline-rich proteins.

SUBMITTER: Robinson R

PROVIDER: S-EPMC1133456 | biostudies-other | 1989 Oct

REPOSITORIES: biostudies-other

ACCESS DATA

Similar Datasets

Project description:Due to the distinctive features of oral mucosa, determination of the proteins involved in the formation of “oral protein pellicle” is demanding. The present study investigated the susceptibility of several human basic proline-rich peptides (bPRPs) named P-H, P-D, P-F, P-J, and II-2 as substrates of transglutaminase-2. The reactivity of P-C peptide and statherin was also investigated. Peptides purified from human whole saliva were incubated at diverse temperatures with two different transglutaminases (type 2; guinea pig and human), in the presence or in the absence of monodansyl-cadaverine. High resolution HPLC-ESI-MS and MS/MS analyses of the reaction products highlighted that P-H, and P-D were active substrates of transglutaminase-2, II-2 was less reactive and the reactivity of P-F and P-J was negligible. All the peptides formed cyclo-derivatives, and only specific glutamine residues were involved in the cycle formation and reacted with monodansyl-cadaverine. Q29 for P-H, Q37 for P-D, and Q21 for II-2 were the principal reactive residues. One or two secondary glutamine residues were hierarchically susceptible to reaction with dansyl-cadaverine. The main consensus sequence recognized by transglutaminase-2 in basic proline-rich peptides was GNPQ, and, despite the great similarity of P-F and P-J with the other salivary peptides, their reactivity was negligible, probably because the GNPQ consensus sequence was missing in their sequence. The reactivity of P-D A32 variant was lower than that of P-D P32 peptide suggesting that the more rigid peptide structure was a better substrates for transglutaminase-2. The reactivity of P-C was high, but followed rules different from the other basic peptides under study, Q41 being the principal reactive residue, confirming that P-C is not strictly related to the basic proline-rich proteins. The reactivity of statherin was very high too, and the manual inspection of the MS/MS fragmentation patterns of the reaction products confirmed, as determined in previous studies, that Q37 is the pivotal residue, Q39 and Q40 the secondary residues recognized by transglutaminase-2. Moreover, Q39 and Q40 residues were more reactive in cyclo-statherin Q37 than in statherin, suggesting that cycle formation increases the reactivity of the secondary glutamine residues. Finally, the physiological temperature (37°C) was the best for the reaction and no significant qualitative differences were observed using human or guinea pig transglutaminase-2.

Dataset Information

Primary structure and possible origin of the non-glycosylated basic proline-rich protein of human submandibular/sublingual saliva.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets