Exploiting Optical Flow Guidance for Transformer-Based Video Inpainting.

Transformers have been widely used for video processing owing to the multi-head self attention (MHSA) mechanism. However, the MHSA mechanism encounters an intrinsic difficulty for video inpainting, since the features associated with the corrupted regions are degraded and incur inaccurate self attention. This problem, termed query degradation, may be mitigated by first completing optical flows and then using the flows to guide the self attention, which was verified in our previous work - flow-guided transformer (FGT). We further exploit the flow guidance and propose FGT++ to pursue more effective and efficient video inpainting. First, we design a lightweight flow completion network by using local aggregation and edge loss. Second, to address the query degradation, we propose a flow guidance feature integration module, which uses the motion discrepancy to enhance the features, together with a flow-guided feature propagation module that warps the features according to the flows. Third, we decouple the transformer along the temporal and spatial dimensions, where flows are used to select the tokens through a temporally deformable MHSA mechanism, and global tokens are combined with the inner-window local tokens through a dual-perspective MHSA mechanism. FGT++ is experimentally evaluated to be outperforming the existing video inpainting networks qualitatively and quantitatively.

Post-traumatic cauda equina nerve calcification: A case report.

BACKGROUND: Post-traumatic cauda equina nerve calcification is extremely rare in clinical practice, and its etiology, pathogenesis, treatment and prognosis are unclear. There are few studies and reports on Post-traumatic cauda equina nerve calcification, and this review reports a case of Post-traumatic cauda equina nerve calcification for reference. CASE SUMMARY: A 52-year-old patient presented to our hospital with a history of lumbar spinal stenosis and a lumbar vertebral fracture caused by trauma. The patient's right lower limb had weakness in hip flexion, knee extension and plantarflexion with muscle strength grade 3, right ankle dorsiflexion and thumb dorsiflexion with muscle strength grade 0. The patient's skin sensation below the right knee plane disappeared. The patient's Computed tomography (CT) data showed signs of cauda equina nerve calcification and the terminal filaments in the plane of the third to fifth lumbar vertebrae. After treatment the patient's symptoms were slightly relieved. CONCLUSION: We provide an extremely rare case of Post-traumatic cauda equina nerve calcification and offer a conservative treatment plan. However, the etiology, mechanism and treatment of Post-traumatic cauda equina nerve calcification are still unclear. This requires scholars to conduct more research and exploration in this area.

First report of Phytophthora blight caused by Phytophthora nicotianae on Daphne odora in China.

The variegated leaves and fragrant flowers of Daphne odora var. marginata Mak. make it a popular garden plant. In May 2020, we found diseased D. odora plants in a greenhouse at the Ganzhou Vegetable and Flower Research Institute, in southeast China; 72% of 1800 plants had Phytophthora blight-like symptoms-shrunken stems, black withered branches, wilted and dropped leaves (Fig 1a), and rotted and dark green roots. The root and stem tissue surfaces were disinfected with 75% ethanol for 30 s followed by 0.1% HgCl2 for 1 min, rinsed thrice with sterile water, and cultured on potato-dextrose agar (PDA) medium at 25°C. Mycelia from the diseased tissue were subcultured on fresh PDA medium, providing three colonies. White colonies (~4.1 mm) were formed after 10 days at 25°C (Fig 1b). Sporangia and chlamydospores were induced by placing actively growing mycelia on PDA medium at 25°C for ~30 days and then at 45°C for ~3 days. Sporangia were ovoid to spherical and 19.33 × 20.99 µm in size (Fig 1c), whereas chlamydospores were spherical and 15.68 × 16.10 µm in size (Fig 1d). All three colonies resembled Phytophthora spp. Genomic DNA was extracted from isolates using the Ezup Column Fungi Genomic DNA Purification Kit (Sangon Biotech [Shanghai] Co. Ltd.), and rDNA-ITS and ß-tubulin were amplified and sequenced. BLAST analysis (GenBank) revealed that the ITS (Accession No. MZ676071) and ß-tubulin (MZ748503) sequences of isolates shared the highest similarity (99-100%) with those of Phytophthora nicotianae (Duccio et al. 2015). A phylogenetic tree of the relationship between our isolate hjt3 and its close relatives within the P. nicotianae species was constructed using the MEGA X neighbor-joining method (Fig 2). The pathogen was identified as P. nicotianae based on morphological and molecular characteristics. Sequencing results of the three samples were consistent, all indicating P. nicotianae. A specimen (JXAU-H2020245) was deposited in the Herbarium of the College of Agronomy, Jiangxi Agricultural University. To confirm pathogenicity, 9-month-old healthy D. odora plants were used for stem and soil inoculation. Stems were cut ~5 cm from the soil with sterilized scalpels and inoculated with 0.8 cm diameter PDA plugs containing actively growing mycelia of isolate hjt3. The soil was sterilized and 0.8 cm PDA plugs containing actively growing mycelia were buried in the soil at ~5 cm; the mycelia were in contact with the roots. Plants in both groups were treated equally; those inoculated with sterile PDA plugs served as controls. There were six plants in each group, with each experiment performed in triplicate. All plants were incubated in a greenhouse at 25-28°C. The stems shrank and began to rot rapidly after 7 days (Fig 3) and the branches turned black and withered within 2 weeks. After soil inoculation, the stems of the inoculated plants blackened and rotted in ~20 days (Fig 4) and the roots rotted and turned dark green (Fig 5). These symptoms rapidly spread to the branches. The control plants did not exhibit any symptoms. Reisolated colonies showed the same morphological traits as the isolates used for inoculation; no target colonies were isolated from the control plants. Phytophthora blight caused by P. nicotianae on D. odora has been reported in Italy (Garibaldi A, 2009) and Korea (Kwon et al. 2005). This is the first detection in China. Therefore, Phytophthora blight on D. odora caused by P. nicotianae should be monitored and controlled to promote the development of the D. odora industry.

Improving the Strapdown Airborne Vector Gravimetry by a Backward Inertial Navigation Algorithm.

Strapdown airborne gravimetry is an efficient way to obtain gravity field data. A new method has been developed to improve the accuracy of airborne vector gravimetry. The method introduces a backward strapdown navigation algorithm into the strapdown gravimetry, which is the reverse process of forward algorithm. Compared with the forward algorithm, the backward algorithm has the same performance in the condition of no sensor error, but has different error characteristics in actual conditions. The differences of the two algorithms in the strapdown gravimetry data processing are presented by simulations, which show that the two algorithms have different performance in the horizontal attitude measurement and convergence of integrated navigation filter. On the basis of detailed analysis, the procedures of accuracy improvement method are presented. The result of this method is very promising when applying to an actual flight test carried out by a SGA-WZ02 strapdown gravimeter. After applying the proposed method, the repeatability of two gravity disturbance horizontal components were 1.83 mGal and 1.80 mGal under the resolution of 6 km, which validate the effectiveness of the method. Furthermore, the wavenumber correlation filter is also discussed as an alternative data fusion method.

Strapdown Airborne Gravimetry Quality Assessment Method Based on Single Survey Line Data: A Study by SGA-WZ02 Gravimeter.

Quality assessment is an important part in the strapdown airborne gravimetry. Root mean square error (RMSE) evaluation method is a classical way to evaluate the gravimetry quality, but classical evaluation methods are preconditioned by extra flight or reference data. Thus, a method, which is able to largely conquer the premises of classical quality assessment methods and can be used in single survey line, has been developed in this paper. According to theoretical analysis, the method chooses the stability of two horizontal attitude angles, horizontal specific force and vertical specific force as the determinants of quality assessment method. The actual data, collected by SGA-WZ02 from 13 flights 21 lines in certain survey, was used to build the model and elaborate the method. To substantiate the performance of the quality assessment model, the model is applied in extra repeat line flights from two surveys. Compared with internal RMSE, standard deviation of assessment residuals are 0.23 mGal and 0.16 mGal in two surveys, which shows that the quality assessment method is reliable and stricter. The extra flights are not necessary by specially arranging the route of flights. The method, summarized from SGA-WZ02, is a feasible approach to assess gravimetry quality using single line data and is also suitable for other strapdown gravimeters.

A New Method for Land Vehicle Gravimetry Using SINS/VEL.

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Optimized Design of the SGA-WZ Strapdown Airborne Gravimeter Temperature Control System.

The temperature control system is one of the most important subsystems of the strapdown airborne gravimeter. Because the quartz flexible accelerometer based on springy support technology is the core sensor in the strapdown airborne gravimeter and the magnet steel in the electromagnetic force equilibrium circuits of the quartz flexible accelerometer is greatly affected by temperature, in order to guarantee the temperature control precision and minimize the effect of temperature on the gravimeter, the SGA-WZ temperature control system adopts a three-level control method. Based on the design experience of the SGA-WZ-01, the SGA-WZ-02 temperature control system came out with a further optimized design. In 1st level temperature control, thermoelectric cooler is used to conquer temperature change caused by hot weather. The experiments show that the optimized stability of 1st level temperature control is about 0.1 °C and the max cool down capability is about 10 °C. The temperature field is analyzed in the 2nd and 3rd level temperature control using the finite element analysis software ANSYS. The 2nd and 3rd level temperature control optimization scheme is based on the foundation of heat analysis. The experimental results show that static accuracy of SGA-WZ-02 reaches 0.21 mGal/24 h, with internal accuracy being 0.743 mGal/4.8 km and external accuracy being 0.37 mGal/4.8 km compared with the result of the GT-2A, whose internal precision is superior to 1 mGal/4.8 km and all of them are better than those in SGA-WZ-01.

An SINS/GNSS Ground Vehicle Gravimetry Test Based on SGA-WZ02.

In March 2015, a ground vehicle gravimetry test was implemented in eastern Changsha to assess the repeatability and accuracy of ground vehicle SINS/GNSS gravimeter-SGA-WZ02. The gravity system developed by NUDT consisted of a Strapdown Inertial Navigation System (SINS), a Global Navigation Satellite System (GNSS) remote station on test vehicle, a GNSS static master station on the ground, and a data logging subsystem. A south-north profile of 35 km along the highway in eastern Changsha was chosen and four repeated available measure lines were obtained. The average speed of a vehicle is 40 km/h. To assess the external ground gravity disturbances, precise ground gravity data was built by CG-5 precise gravimeter as the reference. Under relative smooth conditions, internal accuracy among repeated lines shows an average agreement at the level of 1.86 mGal for half wavelengths about 1.1 km, and 1.22 mGal for 1.7 km. The root-mean-square (RMS) of difference between calculated gravity data and reference data is about 2.27 mGal/1.1 km, and 1.74 mGal/1.7 km. Not all of the noises caused by vehicle itself and experiments environments were eliminated in the primary results. By means of selecting reasonable filters and improving the GNSS observation conditions, further developments in ground vehicle gravimetry are promising.

A Flight Test of the Strapdown Airborne Gravimeter SGA-WZ in Greenland.

An airborne gravimeter is one of the most important tools for gravity data collection over large areas with mGal accuracy and a spatial resolution of several kilometers. In August 2012, a flight test was carried out to determine the feasibility and to assess the accuracy of the new Chinese SGA-WZ strapdown airborne gravimeter in Greenland, in an area with good gravity coverage from earlier marine and airborne surveys. An overview of this new system SGA-WZ is given, including system design, sensor performance and data processing. The processing of the SGA-WZ includes a 160 s length finite impulse response filter, corresponding to a spatial resolution of 6 km. For the primary repeated line, a mean r.m.s. deviation of the differences was less than 1.5 mGal, with the error estimate confirmed from ground truth data. This implies that the SGA-WZ could meet standard geophysical survey requirements at the 1 mGal level.

Experimental investigations on airborne gravimetry based on compressed sensing.

Gravity surveys are an important research topic in geophysics and geodynamics. This paper investigates a method for high accuracy large scale gravity anomaly data reconstruction. Based on the airborne gravimetry technology, a flight test was carried out in China with the strap-down airborne gravimeter (SGA-WZ) developed by the Laboratory of Inertial Technology of the National University of Defense Technology. Taking into account the sparsity of airborne gravimetry by the discrete Fourier transform (DFT), this paper proposes a method for gravity anomaly data reconstruction using the theory of compressed sensing (CS). The gravity anomaly data reconstruction is an ill-posed inverse problem, which can be transformed into a sparse optimization problem. This paper uses the zero-norm as the objective function and presents a greedy algorithm called Orthogonal Matching Pursuit (OMP) to solve the corresponding minimization problem. The test results have revealed that the compressed sampling rate is approximately 14%, the standard deviation of the reconstruction error by OMP is 0.03 mGal and the signal-to-noise ratio (SNR) is 56.48 dB. In contrast, the standard deviation of the reconstruction error by the existing nearest-interpolation method (NIPM) is 0.15 mGal and the SNR is 42.29 dB. These results have shown that the OMP algorithm can reconstruct the gravity anomaly data with higher accuracy and fewer measurements.

Long-term stability of the SGA-WZ strapdown airborne gravimeter.

Accelerometers are one of the most important sensors in a strapdown airborne gravimeter. The accelerometer's drift determines the long-term accuracy of the strapdown inertial navigation system (SINS), which is the primary and most critical component of the strapdown airborne gravimeter. A long-term stability test lasting 104 days was conducted to determine the characteristics of the strapdown airborne gravimeter's long-term drift. This stability test was based on the first set of strapdown airborne gravimeters built in China, the SGA-WZ. The test results reveal a quadratic drift in the strapdown airborne gravimeter data. A drift model was developed using the static data in the two end sections, and then this model was used to correct the test data. After compensating for the drift, the drift effect improved from 70 mGal to 3.46 mGal with a standard deviation of 0.63 mGal. The quadratic curve better reflects the drift's real characteristics. In comparison with other methodologies, modelling the drift as a quadratic curve was shown to be more appropriate. Furthermore, this method allows the drift to be adjusted throughout the course of the entire campaign.

Controlled oxidation of remote sp3 C-H bonds in artemisinin via P450 catalysts with fine-tuned regio- and stereoselectivity.

The selective oxyfunctionalization of isolated sp(3) C-H bonds in complex molecules represents a formidable challenge in organic chemistry. Here, we describe a rational, systematic strategy to expedite the development of P450 oxidation catalysts with refined regio- and stereoselectivity for the hydroxylation of remote, unactivated C-H sites in a complex scaffold. Using artemisinin as model substrate, we demonstrate how a three-tier strategy involving first-sphere active site mutagenesis, high-throughput P450 fingerprinting, and fingerprint-driven P450 reactivity predictions enabled the rapid evolution of three efficient biocatalysts for the selective hydroxylation of a primary and a secondary C-H site (with both S and R stereoselectivity) in a relevant yet previously inaccessible region of this complex natural product. The evolved P450 variants could be applied to provide direct access to the desired hydroxylated derivatives at preparative scales (0.4 g) and in high isolated yields (>90%), thereby enabling further elaboration of this molecule. As an example, enantiopure C7-fluorinated derivatives of the clinical antimalarial drugs artesunate and artemether, in which a major metabolically sensitive site is protected by means of a C-H to C-F substitution, were afforded via P450-mediated chemoenzymatic synthesis.

SGA-WZ: a new strapdown airborne gravimeter.

Inertial navigation systems and gravimeters are now routinely used to map the regional gravitational quantities from an aircraft with mGal accuracy and a spatial resolution of a few kilometers. However, airborne gravimeter of this kind is limited by the inaccuracy of the inertial sensor performance, the integrated navigation technique and the kinematic acceleration determination. As the GPS technique developed, the vehicle acceleration determination is no longer the limiting factor in airborne gravity due to the cancellation of the common mode acceleration in differential mode. A new airborne gravimeter taking full advantage of the inertial navigation system is described with improved mechanical design, high precision time synchronization, better thermal control and optimized sensor modeling. Apart from the general usage, the Global Positioning System (GPS) after differentiation is integrated to the inertial navigation system which provides not only more precise altitude information along with the navigation aiding, but also an effective way to calculate the vehicle acceleration. Design description and test results on the performance of the gyroscopes and accelerations will be emphasized. Analysis and discussion of the airborne field test results are also given.

P450 fingerprinting method for rapid discovery of terpene hydroxylating P450 catalysts with diversified regioselectivity.

Engineered P450 enzymes constitute attractive catalysts for the selective oxidation of unactivated C-H bonds in complex molecules. A current bottleneck in the use of P450 catalysis for chemical synthesis is the time and effort required to identify the P450 variant(s) with the desired level of activity and selectivity. In this report, we describe a method to map the active site configuration of engineered P450 variants in high throughput using a set of semisynthetic chromogenic probes. Through analysis of the resulting 'fingerprints', reliable predictions can be made regarding the reactivity of these enzymes toward complex substrates structurally related to the fingerprint probes. In addition, fingerprint analysis offers a convenient and time-effective means to assess the regioselectivity properties of the fingerprinted P450s. The described approach can represent a valuable tool to expedite the discovery of P450 oxidation catalysts for the functionalization of relevant natural products such as members of the terpene family.

Intramolecular hydrogen bond-controlled prolyl amide isomerization in glucosyl 3(S)-hydroxy-5-hydroxymethylproline hybrids: a computational study.

Peptide mimics containing spirocyclic glucosyl-(3(S)-hydroxy-5(S)-hydroxymethyl)proline (1) and glucosyl-(3(S)-hydroxy-5(R)-hydroxymethyl)proline (2) hybrids differing in the stereochemistry of the polar hydroxymethyl substitutent at the C-5- or (C(delta))-position have been investigated computationally. A computational "build and search" protocol of molecular mechanics systematic search/Monte Carlo search, followed by density functional theory (DFT), has been developed to ensure complete coverage of the large conformational space. Gas-phase DFT optimizations at the B3LYP level of theory lead to a strong preference for the cis conformation in the prolyl amide bond for both compounds 1 and 2. However, inclusion of the solvent water by means of continuum solvation (PCM) results in a reduction of the prolyl amide cis population in both compounds, leading to good agreement with previous experimental observations. Intramolecular hydrogen bonding involving the C-5-hydroxymethyl substitutent is seen to play a crucial role to tune the thermodynamics of prolyl amide cis/trans isomerization and is responsible for the high cis prolyl amide population in compound 2. Our results indicate that H-bond-forming substituents like the hydroxymethyl group at the C-5-position in proline can be used to control cis/trans prolyl amide isomerization. High cis prolyl amide conformer populations can be achieved by proper choice of the stereochemistry at the C-5-position.

Influence of glucose-templated proline mimetics on the beta-turn conformation of the peptide fragment Ac-Leu-D-Phe-Pro-Val-NMe2 found in Gramicidin S.

The synthesis of tetrapeptide-based beta-turn mimetics containing spirocyclic glucose-templated 3-hydroxyproline hybrids Glc3'(S)-5'(R)(CH(2)OH)HypH and Glc3'(S)-5'(S)(CH(2)OH)HypH as proline mimetics is presented. NMR-based conformational analysis of Ac-Leu-D-Phe-[Glc3'(S)-5'(R)(CH(2)OH)HypH]-Val-NMe(2) and Ac-Leu-D-Phe-[Glc3'(S)-5'(S)(CH(2)OH)HypH]-Val-NMe(2) demonstrates the presence of beta-turn conformations. Different turn structures were observed by changing the stereochemistry at 5'-position of Glc3'(S)-5'(R)(CH(2)OH)HypH. The major prolyl amide cis isomer of glucose-protected tetrapeptide Ac-Leu-D-Phe-[Glc(MOM)(4)3'(S)-5'(R)(CH(2)OMOM)HypH]-Val-NMe(2)11 and glucose unprotected Ac-Leu-D-Phe-[Glc3'(S)-5'(R)(CH(2)OH)HypH]-Val-NMe(2)13 forms a type VI beta-turn conformation. In contrast, the major prolyl amide trans rotamer of tetrapeptide Ac-Leu-D-Phe-[Glc(MOM)(4)3'(S)-5'(S)(CH(2)OMOM)HypH]-Val-NMe(2)12 conserves a similar beta-turn conformation as the Gramicidin S-based peptide fragment Ac-Leu-D-Phe-Pro-Val-NMe(2)16.

Intramolecular hydrogen bond-controlled prolyl amide isomerization in glucosyl 3'(S)-hydroxy-5'-hydroxymethylproline hybrids: influence of a C-5'-hydroxymethyl substituent on the thermodynamics and kinetics of prolyl amide cis/trans isomerization.

Peptide mimics containing spirocyclic glucosyl-(3'-hydroxy-5'-hydroxymethyl)proline hybrids (Glc3'(S)-5'(CH(2)OH)HypHs) with a polar hydroxymethyl substituent at the C-5' position, such as C-terminal ester Ac-Glc3'(S)-5'(CH(2)OH)Hyp-OMe and C-terminal amide Ac-Glc3'(S)-5'(CH(2)OH)Hyp-N'-CH(3), were synthesized. C-Terminal esters exhibit increased cis population (23-53%) relative to Ac-3(S)HyPro-OMe (17%) or Ac-Pro-OMe (14%) in D(2)O. The prolyl amide cis population is further increased to 38-74% in the C-terminal amide form in D(2)O. Our study shows that the stereochemistry of the hydroxymethyl substituent at the C-5' position of proline permits tuning of the prolyl amide cis/trans isomer ratio. Inversion-magnetization transfer NMR experiments indicate that the stereochemistry of the hydroxymethyl substituent has a dramatic effect on the kinetics of prolyl amide cis/trans isomerization. A 200-fold difference in the trans-to-cis (k(tc)) isomerization and a 90-fold rate difference in the cis-to-trans (k(ct)) isomerization is observed between epimeric C-5' 3 and 4. When compared to reference peptide mimics Ac-Pro-OMe and Ac-3(S)Hyp-OMe, our study demonstrates that a (13-16)-fold decrease in k(tc) and k(ct) is observed for the C-5'(S), while a (5-24)-fold acceleration is observed for the C-5'(R) epimer. DFT calculations indicate that the pyrrolidine ring prefers a C(beta) exo pucker in both Ac-Glc3'(S)-5'(CH(2)OH)Hyp-OMe diastereoisomers. Computational calculations and chemical shift temperature coefficient (Delta delta/Delta T) experiments indicate that the hydroxymethyl group at C-5' in Ac-Glc3'(S)-5'(CH(2)OH)Hyp-OMe forms a stabilizing intramolecular hydrogen bond to the carbonyl of the N-acetyl group in both epimeric cis isomers. However, a competing intramolecular hydrogen bond between the hydroxymethyl groups in the pyrrolidine ring and pyran ring stabilizes the trans isomer in the C-5'(S) diastereoisomer. The dramatic differences in the kinetic properties of the diastereoisomeric peptide mimics are rationalized by the presence or absence of an intramolecular hydrogen bond between the hydroxymethyl substituent located at C-5' and the developing lone pair on the nitrogen atom of the N-acetyl group in the transition state.

Development of a nitric oxide-releasing analogue of the muscle relaxant guaifenesin for skeletal muscle satellite cell myogenesis.

Nitric oxide (NO) mediates activation of satellite precursor cells to enter the cell cycle. This provides new precursor cells for skeletal muscle growth and muscle repair from injury or disease. Targeting a new drug that specifically delivers NO to muscle has the potential to promote normal function and treat neuromuscular disease, and would also help to avoid side effects of NO from other treatment modalities. In this research, we examined the effectiveness of the NO donor, iosorbide dinitrate (ISDN), and a muscle relaxant, methocarbamol, in promoting satellite cell activation assayed by muscle cell DNA synthesis in normal adult mice. The work led to the development of guaifenesin dinitrate (GDN) as a new NO donor for delivering nitric oxide to muscle. The results revealed that there was a strong increase in muscle satellite cell activation and proliferation, demonstrated by a significant 38% rise in DNA synthesis after a single transdermal treatment with the new compound for 24 h. Western blot and immunohistochemistry analyses showed that the markers of satellite cell myogenesis, expression of myf5, myogenin, and follistatin, were increased after 24 h oral administration of the compound in adult mice. This research extends our understanding of the outcomes of NO-based treatments aimed at promoting muscle regeneration in normal tissue. The potential use of such treatment for conditions such as muscle atrophy in disuse and aging, and for the promotion of muscle tissue repair as required after injury or in neuromuscular diseases such as muscular dystrophy, is highlighted.

Design and synthesis of glucose-templated proline-lysine chimera: polyfunctional amino acid chimera with high prolyl cis amide rotamer population.

We describe the synthesis of two glucose-templated proline-lysine chimeras (GlcTProLysCs) that differ in the stereochemistry of the hydroxymethyl substituent at the C-5' position of the pyrrolidine ring. The key synthetic steps involve C-glycosylation of an exocyclic glucose-based epoxide with allyltributylstannane, which affords functionalized C-ketosides containing an alpha-hydroxy ester moiety; introduction of an amino group at C-2 through stereoselective reductive amination; and regioselective installation of the azide group at C-6 on the glucose scaffold. Incorporation of these chimeras into the model peptides Ac-GlcTProLysC-NHMe and Ac-GlcTProLysC-OMe demonstrates that the stereochemistry of the hydroxymethyl substituent at the C-5' position has a profound effect on the equilibrium constant of prolyl amide cis/trans isomerization. The equilibrium constant K(c/t) for the peptide mimic Ac-GlcTProLysC-NHMe with C-5'(R) stereochemistry was determined to be 3.03+/-0.04, while the K(t/c) for the C-5'(S) diastereoisomer was 0.56+/-0.04 in D(2)O. Temperature coefficient experiments indicate that the origin of these effects is derived from two critical hydrogen bonds involving the C-5' hydroxymethyl substituent: one to the N-terminal amide carbonyl group, and the other to the primary amino group in the glucose moiety.