The Open Protein Structure Annotation Network
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    Table of contents
    1. 1. Protein Summary
    2. 2. Ligand Summary

    Title Crystal structure of intracellular proteinase inhibitor (NP_388994.1) from BACILLUS SUBTILIS at 2.61 A resolution. To be published
    Site JCSG
    PDB Id 3isy Target Id 392216
    Molecular Characteristics
    Source Bacillus subtilis subsp. subtilis str. 168
    Alias Ids TPS24345,NP_388994.1, 323939 Molecular Weight 14073.13 Da.
    Residues 119 Isoelectric Point 4.89
    Sequence menqevvlsidaiqepeqikfnmslknqseraiefqfstgqkfelvvydsehkeryryskekmftqafq nltlesgetydfsdvwkevpepgtyevkvtfkgraenlkqvqavqqfevk
      BLAST   FFAS

    Structure Determination
    Method XRAY Chains 1
    Resolution (Å) 2.61 Rfree 0.243
    Matthews' coefficent 3.15 Rfactor 0.203
    Waters 21 Solvent Content 60.93

    Ligand Information


    Google Scholar output for 3isy

    Protein Summary

    The gene BSU11130 encodes the protein NP_388994, an intracelluar proteinase inhibitor from Bacillus subtilis (BsuPI) whose structure (3isy) has been determined at a resolution of 2.6 Angstroms. BsuPI is a first structurally characterized protein from a large family (over 60 members, now assigned as BsuPI/PF12690 in PFAM, part of Ig-like fold CL0159) novel protein family, not defined in PFAM nor any other protein classification resource. Proteins from this family are found mostly in Firmicutes (Bacillii and Clostridia), but also in gamma-proteobacteria (Shewanella) and psychrophilic (adapted to low temperature) and alkaliphiloic (adapted to high pH) archea ( Halorubrum lacusprofundi and Natronomonas pharaonis). Interestingly, JCSG solved protein represents a minimal core of this family, as most homologs contain an extra N-terminal fragment of 20-40 amino acids. Homologous domains are also found in larger proteins with diverse functions.

    BsuPI is distantly homologous to various bacterial proteins with greek key beta barrel topologies. These homologies are confirmed by the experimentally determined structure of BsuPI, which shows long loops forming an additional beta-sheet. DALI provides weak hits (Z=10) with the coagulation factor XIII chain A proteins 1ex0, 1ggu, 1evu, 1ggy.

    The residues that important functionally can be identified by sequence conservation analysis as these residues clustered on a single location (56-68, 37-46). Note, these residues are distributed on both sides of the molecule (only one side is shown in Figure 2).


    Figure 1. Monomer of 3isy


    Figure 2. Important residues are clustered together (blue (not conserved) ---> red (conserved))


    Figure 3. Sequence alignment



    Shiga Y, Yamagata H, Udaka S.
    Characterization of the gene encoding an intracellular proteinase inhibitor of Bacillus subtilis and its role in regulation of the major intracellular proteinase.J Bacteriol. 1993 Nov;175(22):7130-7. PMID: 8226659

    Millet, J. 1979. Characterization of an inhibitor of the intracellular protease from Bacillus subtilis. Biochimie 61:385-391.

    Ligand Summary




    No references found.

    Tag page

    Files (3)

    FileSizeDateAttached by 
    sequence alignment of homologs for BsuPI
    36.22 kB20:59, 19 May 2009qxuActions
    conservation colored (red=conserved)
    450.54 kB21:05, 19 May 2009qxuActions
    monomer of fr15301a
    151.31 kB20:20, 19 May 2009qxuActions
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