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Adelinda Yee

Publications and source records attributed to Adelinda Yee.

At least 19 recordsLinked to original sources

Solution NMR in structural genomics.

Structural genomics (also known as structural proteomics) aims to generate accurate three-dimensional models for all folded, globular proteins and domains in the protein universe to understand the relationship between protein sequence, structure and function. NMR spectroscopy of small (<20 kDa) proteins has been used successfully within several large-scale structural genomics projects for more than six years now. Recent advances coming from traditional NMR structural biology laboratories as well as large scale centers and consortia using NMR for structural genomics promise to facilitate NMR analysis making it even a more efficient and increasingly automated procedure.

Animals↗

MTH187 from Methanobacterium thermoautotrophicum has three HEAT-like repeats.

With the completion of genome sequencing projects, there are a large number of proteins for which we have little or no functional information. Since protein function is closely related to three-dimensional conformation, structural proteomics is one avenue where the role of proteins with unknown function can be investigated. In the present structural project, the structure of MTH187 has been determined by solution-state NMR spectroscopy. This protein of 12.4 kDa is one of the 424 non-membrane proteins that were cloned and purified for the structural proteomic project of Methanobacterium thermoautotrophicum [Christendat, D., Yee, A., Dharamsi, A., Kluger, Y., Gerstein, M., Arrowsmith, C.H. and Edwards, A.M. (2000) Prog. Biophys. Mol. Biol., 73, 339-345]. Methanobacterium thermoautotrophicum is a thermophilic archaeon that grows optimally at 65 degrees C. A particular characteristic of this microorganism is its ability to generate methane from carbon dioxide and hydrogen [Smith, D.R., Doucette-Stamm, L.A., Deloughery, C., Lee, H., Dubois, J., Aldredge, T., Bashirzadeh, R., Blakely, D., Cook, R., Gilbert, K., Harrison, D., Hoang, L., Keagle, P., Lumm, W., Pothier, B., Qiu, D., Spadafora, R., Vicaire, R., Wang, Y., Wierzbowski, J., Gibson, R., Jiwani, N., Caruso, A., Bush, D., Reeve, J. N. et al. (1997) J. Bacteriol., 179, 7135-7155].

Archaeal Proteins↗

Solution structure of the Escherichia coli protein ydhR: a putative mono-oxygenase.

YdhR is a 101-residue conserved protein from Escherichia coli. Sequence searches reveal that the protein has >50% identity to proteins found in a variety of other bacterial genomes. Using size exclusion chromatography and fluorescence spectroscopy, we determined that ydhR exists in a dimeric state with a dissociation constant of approximately 40 nM. The three-dimensional structure of dimeric ydhR was determined using NMR spectroscopy. A total of 3400 unambiguous NOEs, both manually and automatically assigned, were used for the structure calculation that was refined using an explicit hydration shell. A family of 20 structures was obtained with a backbone RMSD of 0.48 A for elements of secondary structure. The structure reveals a dimeric alpha,beta fold characteristic of the alpha+beta barrel superfamily of proteins. Bioinformatic approaches were used to show that ydhR likely belongs to a recently identified group of mono-oxygenase proteins that includes ActVA-Orf6 and YgiN and are involved in the oxygenation of polyaromatic ring compounds.

Amino Acid Sequence↗

Solution structure of YKR049C, a putative redox protein from Saccharomyces cerevisiae.

YKR049C is a mitochondrial protein in Saccharomyces cerevisiae that is conserved among yeast species, including Candida albicans. However, no biological function for YKR049C has been ascribed based on its primary sequence information. In the present study, NMR spectroscopy was used to determine the putative biological function of YKR049C based on its solution structure. YKR049C shows a well-defined thioredoxin fold with a unique insertion of helices between two beta-strands. The central beta-sheet divides the protein into two parts; a unique face and a conserved face. The 'unique face' is located between beta2 and beta3. Interestingly, the sequences most conserved among YKR049C families are found on this 'unique face', which incorporates L109 to E114. The side chains of these conserved residues interact with residues on the helical region with a stretch of hydrophobic surface. A putative active site composed by two short helices and a single Cys97 was also well observed. Our findings suggest that YKR049C is a redox protein with a thioredoxin fold containing a single active cysteine.

Amino Acid Sequence↗

NMR data collection and analysis protocol for high-throughput protein structure determination.

A standardized protocol enabling rapid NMR data collection for high-quality protein structure determination is presented that allows one to capitalize on high spectrometer sensitivity: a set of five G-matrix Fourier transform NMR experiments for resonance assignment based on highly resolved 4D and 5D spectral information is acquired in conjunction with a single simultaneous 3D 15N,13C(aliphatic),13C(aromatic)-resolved [1H,1H]-NOESY spectrum providing 1H-1H upper distance limit constraints. The protocol was integrated with methodology for semiautomated data analysis and used to solve eight NMR protein structures of the Northeast Structural Genomics Consortium pipeline. The molecular masses of the hypothetical target proteins ranged from 9 to 20 kDa with an average of approximately 14 kDa. Between 1 and 9 days of instrument time were invested per structure, which is less than approximately 10-25% of the measurement time routinely required to date with conventional approaches. The protocol presented here effectively removes data collection as a bottleneck for high-throughput solution structure determination of proteins up to at least approximately 20 kDa, while concurrently providing spectra that are highly amenable to fast and robust analysis.

Data Collection↗

NMR solution structure of Thermotoga maritima protein TM1509 reveals a Zn-metalloprotease-like tertiary structure.

The 150-residue protein TM1509 is encoded in gene YF09_THEMA of Thermotoga maritima. TM1509 has so far no functional annotation and belongs to protein family UPF0054 (PFAM accession number: PF02130) which contains at least 146 members. The NMR structure of TM1509 reveals an alpha+beta fold comprising a four stranded beta-sheet with topology A( upward arrow), B( upward arrow), D( upward arrow), C( downward arrow) as well as five alpha-helices I-V. The structures of most members of family PF02130 can be reliably constructed using the TM1509 NMR structure, demonstrating high leverage for exploration of fold space. A multiple sequence alignment of TM1509 with homologues of family UPF0054 shows that three polypeptide segments, as well as a putative zinc-binding consensus motif HGXLHLXGYDH located at the C-terminal end of alpha-helix IV, are highly conserved. The spatial arrangement of the three His residues of this UPF0054 consensus motif is similar to the arrangement found for the His residues in the HEXXHXXGXXH zinc-binding consensus motif of matrix metallo-proteases (MMPs). Moreover, the other conserved polypeptide segments form a large cavity which encloses the putative Zn-binding pocket and might confer specificity during catalysis. However, TM1509 and the other members of the UPF0054 family do not have the crucial Glu residue in position 2 of the MMP consensus motif. Intriguingly, the TM1509 structure indicates that the Asp in the UPF0054 consensus motif (Asp 111 in TM1509) may overtake the catalytic role of the Glu. This suggests that protein family UPF0054 might contain members of a hitherto uncharacterized class of metalloproteases.

Amino Acid Sequence↗

A novel member of the YchN-like fold: solution structure of the hypothetical protein Tm0979 from Thermotoga maritima.

We report herein the NMR structure of Tm0979, a structural proteomics target from Thermotoga maritima. The Tm0979 fold consists of four beta/alpha units, which form a central parallel beta-sheet with strand order 1234. The first three helices pack toward one face of the sheet and the fourth helix packs against the other face. The protein forms a dimer by adjacent parallel packing of the fourth helices sandwiched between the two beta-sheets. This fold is very interesting from several points of view. First, it represents the first structure determination for the DsrH family of conserved hypothetical proteins, which are involved in oxidation of intracellular sulfur but have no defined molecular function. Based on structure and sequence analysis, possible functions are discussed. Second, the fold of Tm0979 most closely resembles YchN-like folds; however the proteins that adopt these folds differ in secondary structural elements and quaternary structure. Comparison of these proteins provides insight into possible mechanisms of evolution of quaternary structure through a simple mechanism of hydrophobicity-changing mutations of one or two residues. Third, the Tm0979 fold is found to be similar to flavodoxin-like folds and beta/alpha barrel proteins, and may provide a link between these very abundant folds and putative ancestral half-barrel proteins.

Amino Acid Sequence↗