Disease relevance of MMAB

• Here two common polymorphic variants of the ATR that are found in normal individuals are expressed in Escherichia coli, purified, and partially characterized [1].
• In Listeria monocytogenes the acid tolerance response (ATR) takes place through a programmed molecular response which ensures cell survival under unfavorable conditions [2].
• Adaptive acid tolerance response (ATR) in Aeromonas hydrophila [3].
• Previous research with Streptococcus mutans and other oral streptococci has demonstrated that the acid shock of exponential-phase cells (pH 7.5 to 5.5) resulted in the induction of an acid tolerance response (ATR) increasing survival at low pH (3.5-3.0) [4].
• CONCLUSIONS: Culturing L. monocytogenes and Salmonella to stationary phase in media with 1% glucose induces a pH-dependent ATR and enhances their survival to organic acids; thus, this method is suitable for producing acid-adapted cultures for use in food challenge studies [5].

High impact information on MMAB

• ATM and ATR share highly overlapping substrate specificities and show a strong preference for the phosphorylation of Ser or Thr residues followed by Gln [6].
• The functionally related ATM (ataxia telangiectasia-mutated) and ATR (ATM-Rad3-related) protein kinases are critical regulators of DNA damage responses in mammalian cells [6].
• Investigations also showed that purified recombinant human methionine synthase reductase (MSR) in combination with purified ATR can convert cob(II)alamin to AdoCbl in vitro [1].
• The data presented here indicate that the consecutive actions of ATR-CHK1 and CDK2 kinases are involved in this phosphorylation in the presence of hydroxyurea [7].
• Much evidence links ATR with virulence, but the molecular determinants involved in the reactivity to low pHs and the behavior of acid-exposed bacteria within host cells are still poorly understood [2].

Biological context of MMAB

• We confirmed mitochondrial expression of MMAB in human cells and showed that two mutations, R186W and E193K, were associated with absent protein by Western blot, while one, R191W, coupled with another point mutation, produced a protein in patient fibroblasts [8].
• Potential regulatory motifs involved in the ATR were identified in the promoter regions of some of the regulated genes [9].
• No consistent, positive or negative, influence of antibiotic resistance on the pH-inducible ATR or acid resistance (AR) was observed [5].

Anatomical context of MMAB

• The MMAA protein likely transports Cbl into the mitochondria for adenosylcobalamin synthesis, while the MMAB protein appears to be an adenosyltransferase [10].

Associations of MMAB with chemical compounds

• ATP:cob(I)alamin adenosyltransferase (MMAB protein; methylmalonic aciduria type B) is an enzyme of vitamin B(12) metabolism that converts reduced cob(I)alamin to the adenosylcobalamin co-factor required for the functional activity of methylmalonyl-CoA mutase [8].
• A. brasilense can grow and produce IAA in batch cultures between 20 and 38 degrees C in a standard minimal medium (MMAB) containing 2.5 gl(-1)l-malate and 50 microgml(-1) tryptophan [11].
• Protein neosynthesis was shown to be required for optimal ATR, since chloramphenicol reduced the acquired acid tolerance [12].
• All four strains were unable to generate a stationary-phase ATR under control conditions at pH 7.5, with the exception of a burst of survivors in the transition between the exponential and stationary phases when the carbon source (glucose) was depleted [4].

Other interactions of MMAB

• MMAB encodes the enzyme ATP:cobalamin adenosyltransferase, which catalyzes the synthesis of the coenzyme adenosylcobalamin required for the activity of the mitochondrial enzyme methylmalonyl CoA mutase (MCM) [13].

Analytical, diagnostic and therapeutic context of MMAB

• The electrodeposited SWNT films were characterized by using Raman spectroscopy, attenuated total reflectance infrared (ATR/IR) spectrometry and atomic force microscopy [14].

References