HYDROXYLATION AT VAL-120; ASN-126; VAL-128 AND ASN-134
the marine sponge polytheonamide b (ptb) family
Nitrile hydratase alpha /Thiocyanate hydrolase gamma
Antimicrobial peptide active against Gram-positive bacteria (MIC=4->125 ug/ml) (PubMed:22983711). May act by forming transmembrane ion channels, since the peptide rapidly depolarizes the bacterial cytoplasmic membrane, simultaneously decreasing the membrane potential and intracellular potassium contents (PubMed:22983711).
Epimerization of most, and perhaps all, L- to D-amino acids is catalyzed by PoyD, when PoyA and PoyD are coexpressed in E.coli.
N-methylations are catalyzed by PoyE, when PoyA and PoyE are coexpressed in E.coli.
To obtain 2-oxo-5,5-dimethylhexanoate, Thr-97 is firstly dehydrated by PoyF (PubMed:22983711). The second step possibly corresponds to methylation by PoyB/C, and the third step may be a cleavage by PoyH/J (Probable).
The name 'proteusin' is inspired by Proteus, a Greek shape-shifting sea god.
Compared to polytheonamide B, polytheonamide A has an additional sulfoxide moiety at Met-141, which arises from spontaneous oxidation during polytheonamide isolation.
X-RAY CRYSTALLOGRAPHY (2.09 ANGSTROMS) OF 2-379 IN COMPLEX WITH COENZYME A AND SUBSTRATE
Involved in the catabolism of short chain fatty acids (SCFA) via the tricarboxylic acid (TCA)(acetyl degradation route) and via the 2-methylcitrate cycle I (propionate degradation route). Catalyzes the Claisen condensation of propionyl-CoA and oxaloacetate (OAA) to yield 2-methylcitrate (2-MC) and CoA. Also catalyzes the condensation of oxaloacetate with acetyl-CoA but with a lower specificity.
kcat is 8 sec(-1) for 2-methylcitrate synthase activity with propionyl-CoA as substrate (at pH 8 and 23 degrees Celsius). kcat is 21 sec(-1) for citrate synthase activity with acetyl-CoA as substrate (at pH 8 and 23 degrees Celsius).
3 uM for oxaloacetate (with propionyl-CoA at pH 8 and 23 degrees Celsius)
6.9 uM for oxaloacetate (with acetyl-CoA at pH 8 and 23 degrees Celsius)
7 uM for oxaloacetate (with acetyl-CoA at pH 8 and 23 degrees Celsius)
16 uM for propionyl-CoA (at pH 8 and 23 degrees Celsius)
229 uM for acetyl-CoA (at pH 8 and 23 degrees Celsius)
230 uM for acetyl-CoA (at pH 8 and 23 degrees Celsius)
12 umol/min/mg enzyme with propionyl-CoA as substrate (at pH 8 and 23 degrees Celsius)
30 umol/min/mg enzyme with acetyl-CoA as substrate (at pH 8 and 23 degrees Celsius)
Optimum temperature is 31 degrees Celsius. Cold-active. Is rapidly inactivated at 45 degrees Celsius, and shows significant activity at 10 degrees Celsius and below.
By growth on propionate, but not acetate or glucose.
39S RIBOSOMAL PROTEIN L12, MITOCHONDRIAL
Ribosomal protein L7/12, oligomerisation (N-terminal) domain
Seems to be the binding site for several of the factors involved in protein synthesis and appears to be essential for accurate translation.
Forms part of the ribosomal stalk which helps the ribosome interact with GTP-bound translation factors. Is thus essential for accurate translation.
Homodimer. Part of the ribosomal stalk of the 50S ribosomal subunit. Forms a multimeric L10(L12)X complex, where L10 forms an elongated spine to which 2 to 4 L12 dimers bind in a sequential fashion. Binds GTP-bound translation factors.
Belongs to the bacterial ribosomal protein bL12 family.
Belongs to the sulfate adenylyltransferase family.