Aaron Springer

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Aerobic gram-negative methylotrophs oxidize methanol to formaldehyde by using a methanol dehydrogenase that has pyrroloquinoline quinone (PQQ) as a prosthetic group. Seventy-two mutants which are unable to grow on methanol unless the growth medium is supplemented with PQQ have been isolated in the facultative methanol utilizer Methylobacterium extorquens(More)
In the facultative serine cycle methylotroph Methylobacterium extorquens AM1, mxaB is required for regulation of methanol oxidation and is located at the end of a large cluster of methylotrophy genes that begins with mxaF. The sequence of mxaB has been obtained and indicates that the gene product is a member of the response regulator family. None of the(More)
Two-hundred-and-eight new Methylobacterium extorquens AM1 methanol oxidation (Mox) mutants were isolated and placed into complementation groups. Complementation analyses identified new Mox groups in the Mxb and Mxc loci and at a new locus, Mxd. Thirty-seven mutants at the Mxb locus were divided into MxbM and MxbD complementation groups on the basis of their(More)
Five genes are thought to be required for transcription of methanol oxidation genes in Methylobacterium strains. These putative regulatory genes include mxcQE, which encode a putative sensor-regulator pair, and mxbDM and mxaB, whose functions are less well-understood. In this study, mxbDM in Methylobacterium extorquens AM1 were shown to be required for(More)
Thirteen conditional lethal mutations in genes of Salmonella typhimurium map at the clmF locus and affect both viability and the faithful partitioning of daughter nucleoids. These mutations have now been divided into three complementation groups by using cloned fragments of S. typhimurium DNA and renamed parC, parE, and parF. The proteins produced from the(More)
Methylobacterium extorquens AM1 pqqEF are genes required for synthesis of pyrroloquinoline quinone (PQQ). The nucleotide sequence of these genes indicates PqqE belongs to an endopeptidase family, including PqqF of Klebsiella pneumoniae, and M. extorquens AM1 PqqF has low identity with the same endopeptidase family. M. extorquens AM1 pqqE complemented a K.(More)
The DNA sequence of the wild type S. typhimurium parE gene was determined. The predicted protein has 96.7% amino acid identity with the ParE protein of E.coli, but is 29 amino acids longer, due to an additional basepair in the 3' end of the S. typhimurium gene. Subclones of the S. typhimurium parE gene localized the sites of four heat sensitive mutations(More)
Examining student interactions in multi-step problems from Intelligent Tutoring Systems currently involves examining thousands of interactions from hundreds of students. We designed and implemented a sequential pattern mining algorithm and a sequence rating algorithm that together recognize interesting student action sequences and display them to the user(More)
RNA polymerase (RNAP) was purified from Methylobacterium extorquens AM1 cells grown on methanol or on succinate. The beta, beta', alpha and omega subunits were approximately the same size as those of Escherichia coli, and the identity of the omega subunit was confirmed by N-terminal sequence analysis. N-terminal sequence analysis suggested that two other(More)