Many structures and molecules closely related to those involved in the specific process of immunoglobulin (Ig) hypermutation existed before the appearance of primordial Ig genes. Consequently, these structures can be found even in animals and organisms distinct from vertebrates; likewise, homologues of hypermutation enzymes are present in a broad range of species, from bacteria to mammals. Our analysis, based predominantly on primary structure, demonstrates the existence of molecules similar to Ig domains, variable Ig domains (IGv), and antigen receptors (AR) in unicellular organisms, nonvertebrate metazoans, and nonvertebrate Coelomata, respectively. In addition, we deal here with some important structural properties of CDR1-like segments of the selected sponge adhesion molecule GCSAMS exhibiting chimerical Ig domain similarities, and demonstrate the occurrence of conserved regions corresponding to Ohno's modern intact primordial building block in the C-terminal part of IGv-related segments of nonvertebrate origin. The results of our analysis are also discussed with respect to the possible phylogeny of molecules preceding the hypothetical common antigen receptor ancestor.

• MeSH
• fylogeneze * MeSH
• geny pro imunoglobuliny genetika   MeSH
• lidé MeSH
• molekulární evoluce MeSH
• molekulární sekvence - údaje MeSH
• mutace * MeSH
• mutační analýza DNA metody   MeSH
• sekvence aminokyselin MeSH
• sekvenční seřazení MeSH
• výpočetní biologie metody   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Sequences of immunoglobulin (Ig) domains of adhesive molecule GSAMS from the living fossil sponge Geodia cydonium were compared with the important motif of peptide protein kinase substrates and inhibitors (PKSI), detail PKSI sequences, and a common template sequence, derived from structures determined previously. We found the site-restricted sequence similarities to these peptide sequences predominantly in the GSAM Ig1 domain of GSAMS in the domain region related to corresponding Ig similarities detected earlier. Additional sequence block-related analysis revealed the presence of CDR1-like segments within PKSI-related regions and resulted in the detection of increased numbers of hypermutation motifs just in the CDR1-like segment of GSAM Ig1 (GSAM(cdrl.1)). In the following database searches with PKSI-related regions and GSAM(cdr1.1) we looked for: (i) peptide similarities present in the context of Ig domains or related structures in a large range of species from Archaea to Vertebrata, and (ii) some special nucleotide similarities.

• MeSH
• aminokyselinové motivy MeSH
• aminokyseliny analýza   MeSH
• biologická evoluce MeSH
• databáze faktografické MeSH
• imunoglobuliny genetika   metabolismus   MeSH
• inhibitory proteinkinas * MeSH
• molekuly buněčné adheze chemie   genetika   MeSH
• Porifera genetika   MeSH
• proteinkinasy metabolismus   MeSH
• sekvence aminokyselin MeSH
• sekvenční homologie aminokyselin * MeSH
• sekvenční seřazení MeSH
• somatická hypermutace imunoglobulinových genů MeSH
• zkameněliny MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• aminokyseliny MeSH
• imunoglobuliny MeSH
• inhibitory proteinkinas * MeSH
• molekuly buněčné adheze MeSH
• proteinkinasy MeSH