Methods and apparatus for sequencing polymers with a statistical certainty using mass spectrometry
First Claim
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1. A method of obtaining sequence information about a polymer comprising a plurality of monomers of known mass, said method comprising the steps of:
- a) providing a processor in communication with a mass spectrometer;
b) providing a set of polymer fragments, each polymer fragment differing from each other polymer fragment by one or more of the monomers of known mass;
c) measuring a difference x between the mass-to-charge ratio of one pair of polymer fragments with the mass spectrometer;
d) repeating step c) a number of times, n, where n is at least two, using the processor to determine a measured mean mass-to-charge ratio difference. x, between the pair of polymer fragments;
e) asserting a mean difference, μ
, between the mass-to-charge ratio of the pair of polymer fragments measured in step c) using the processor, wherein μ
corresponds to a known mass-to-charge ratio of one monomer of the plurality of monomers of known mass;
f) selecting a desired confidence level for μ
;
g) analyzing x with the processor to determine if x is statistically different from μ
at the selected confidence level;
h) determining with the processor if the asserted mean, μ
, is not statistically different from the measured mean mass-to-charge ratio difference, x, at the selected confidence level based upon the analysis in step g) and if μ
is not statistically different, uniquely assigning one of the pair of polymer fragments to a monomer of the plurality of monomers of known mass corresponding to the mean difference μ
;
i) if the asserted mean μ
, is statistically different from the measured mean mass-to-charge ratio difference, x at the selected confidence level based upon the analysis in step g) then repeating steps e) through h) for a plurality of desired values of μ
, each value of μ
corresponding to one monomer of the plurality of monomers of known mass; and
j) if after performing step i) a unique assignment of one of the pair of polymer fragments has not been made to one monomer of the plurality of monomers of known mass, then automatically repeating steps d) through i) using the processor and the mass spectrometer for a larger number of times n.
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Abstract
Integrated methods and apparatus for sequencing or identifying polymers by mass spectrometry with a statistical certainty. The methods involve integrating data obtained by mass spectrometry analysis of a series of polymer fragments and statistically comparing said data with hypothetical data corresponding to known sequences or identities.
70 Citations
47 Claims
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1. A method of obtaining sequence information about a polymer comprising a plurality of monomers of known mass, said method comprising the steps of:
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a) providing a processor in communication with a mass spectrometer; b) providing a set of polymer fragments, each polymer fragment differing from each other polymer fragment by one or more of the monomers of known mass; c) measuring a difference x between the mass-to-charge ratio of one pair of polymer fragments with the mass spectrometer; d) repeating step c) a number of times, n, where n is at least two, using the processor to determine a measured mean mass-to-charge ratio difference. x, between the pair of polymer fragments; e) asserting a mean difference, μ
, between the mass-to-charge ratio of the pair of polymer fragments measured in step c) using the processor, wherein μ
corresponds to a known mass-to-charge ratio of one monomer of the plurality of monomers of known mass;f) selecting a desired confidence level for μ
;g) analyzing x with the processor to determine if x is statistically different from μ
at the selected confidence level;h) determining with the processor if the asserted mean, μ
, is not statistically different from the measured mean mass-to-charge ratio difference, x, at the selected confidence level based upon the analysis in step g) and if μ
is not statistically different, uniquely assigning one of the pair of polymer fragments to a monomer of the plurality of monomers of known mass corresponding to the mean difference μ
;i) if the asserted mean μ
, is statistically different from the measured mean mass-to-charge ratio difference, x at the selected confidence level based upon the analysis in step g) then repeating steps e) through h) for a plurality of desired values of μ
, each value of μ
corresponding to one monomer of the plurality of monomers of known mass; andj) if after performing step i) a unique assignment of one of the pair of polymer fragments has not been made to one monomer of the plurality of monomers of known mass, then automatically repeating steps d) through i) using the processor and the mass spectrometer for a larger number of times n. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 46, 47)
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18. A method for obtaining sequence information about a polymer comprising a series of different monomers of known mass, said method comprising the steps of:
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a) hydrolyzing a pole with a hydrolyzing agent wherein the hydrolysis is performed on a reaction surface, said surface providing spatially separate differing amounts of a hydrolyzing agent, said hydrolysis creating a set of polymer fragments, each polymer fragment differing from each other polymer fragment by one or more of the monomers of known mass; b) measuring a difference x between the mass-to-charge ratio of one pair of polymer fragments; c) repeating step b) a number of times, n, where n is at least two, to determine a measured mean mass-to-charge ratio difference, x, between the pair of polymer fragments; d) asserting a mean difference, μ
, between the mass-to-charge ratio of the pair of polymer fragments measured in step b, wherein μ
corresponds to a known mass-to-charge ratio of one of the monomers of known mass;e) selecting a desired confidence level for μ
;f) determining the standard deviation s of the measured mean mass-to-charge ratio difference x determined in step c; g) calculating a test statistic tcalculated with the following algorithm;
##EQU5## h) comparing the test statistic tcalculated calculated in step g to a t-distribution corresponding to the number of measurements, n, and the desired confidence level; andi) determining if the asserted mean μ
is not substantially different from the measured mean mass-to-charge ratio difference, x, at the selected confidence level based upon the comparison in step h. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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32. A method for obtaining sequence information about a polymer having a plurality of monomers of known mass, said method comprising:
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a) hydrolyzing a polymer with a hydrolyzing agent wherein the bydrolysis is performed on a reaction surface, said surface providing spatially separate differing amounts of a hydrolyzing agent, said hydrolysis creating a set of polymer fragments, each polymer fragment differing from each other polymer fragment by one or more of the monomers of known mass; b) determining a measured mean mass-to-charge ratio difference, x between one pair of polymer fragments; c) asserting a mean difference, μ
, between the mass-to-charge ratio of the pair of polymer fragments measured in step b, wherein μ
corresponds to a known mass-to-charge ratio of one of the monomers of known mass;d) selecting the desired confidence level for μ
;e) analyzing x to determine if it is statistically different from μ
at the selected confidence level;f) repeating steps b)-e) a number of times, n, until a plurality of desired values of μ
have been asserted;g) determining if the asserted mean μ
is not substantially different from the measured mean mass-to-charge ratio difference, x, at the selected confidence level based upon the analysis in step e; andh) repeating steps b)-g) for additional pairs of fragments. - View Dependent Claims (33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45)
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Specification