Prosecution Insights
Last updated: April 19, 2026
Application No. 18/549,838

NOVEL CITRATE SYNTHASE VARIANT AND METHOD FOR PRODUCING L-AMINO ACIDS USING SAME

Non-Final OA §103§112§DP
Filed
Sep 08, 2023
Examiner
WHITE, ASHLEY TAYLOR
Art Unit
1653
Tech Center
1600 — Biotechnology & Organic Chemistry
Assignee
Cj Cheiljedang Corporation
OA Round
1 (Non-Final)
36%
Grant Probability
At Risk
1-2
OA Rounds
3y 5m
To Grant
99%
With Interview

Examiner Intelligence

Grants only 36% of cases
36%
Career Allow Rate
4 granted / 11 resolved
-23.6% vs TC avg
Strong +78% interview lift
Without
With
+77.8%
Interview Lift
resolved cases with interview
Typical timeline
3y 5m
Avg Prosecution
48 currently pending
Career history
59
Total Applications
across all art units

Statute-Specific Performance

§101
10.0%
-30.0% vs TC avg
§103
39.8%
-0.2% vs TC avg
§102
18.4%
-21.6% vs TC avg
§112
22.7%
-17.3% vs TC avg
Black line = Tech Center average estimate • Based on career data from 11 resolved cases

Office Action

§103 §112 §DP
DETAILED ACTION Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Priority This application claims benefit of priority to Republic of Korea Application No. KR10-2021-0031641 filed 03/10/2021 and is also a 371 of PCT/KR2022/003359 filed 03/10/2022. Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55. However, an English translation of the foreign patent document was not filed. Therefore, for the purposes of applying prior art, the effective filing date of the claimed invention is the date of the PCT, 03/10/2022. Information Disclosure Statement The Information Disclosure Statements filed 09/08/2023 and 12/31/2024 have been acknowledged and considered. Election/Restrictions Applicant’s election of SEQ ID NO: 8 as the specific citrate synthase variant, Asparagine as X1, Alanine as X2 and Tyrosine as X3 in the reply filed on 02/19/2026 is acknowledged. Because applicant did not distinctly and specifically point out the supposed errors in the restriction requirement, the election has been treated as an election without traverse (MPEP § 818.01(a)). Specifically, Applicant did not indicate whether the election was made with or without traverse. Claim Status Claims 1-15 are currently pending and under examination. Claim Rejections - 35 USC § 112 The following is a quotation of 35 U.S.C. 112(b): (b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention. The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph: The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention. Claims 1-15 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention. Claim 1 recites “corresponding to position 415 of the amino acid sequence of SEQ ID NO: 1” in lines 1-2. It is unclear whether position 415 is referring to the modified polypeptide being claimed, or to SEQ ID NO: 1. Thus, claim 1 is indefinite. Additionally, all claims dependent upon claim 1 are rendered indefinite as they do not clear up the indefiniteness of claim 1. Claim 3 recites “the variant comprises a polypeptide represented by the amino acid sequence of SEQ ID NO: 3” in lines 1-2. It is unclear what “represented by” means. It is unclear if the variant comprises any of the SEQ ID NOs because it is unclear what represented by means. Claim 4 recites “the variant comprises a polypeptide represented by ….” in lines 1-2 and gives a specific amino acid sequence. It is unclear what “represented by” means. It is unclear if the variant comprises the sequence given or not because it is unclear what represented by means. Claim Rejections - 35 USC § 103 The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows: 1. Determining the scope and contents of the prior art. 2. Ascertaining the differences between the prior art and the claims at issue. 3. Resolving the level of ordinary skill in the pertinent art. 4. Considering objective evidence present in the application indicating obviousness or nonobviousness. This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention. Claims 1-15 are rejected under 35 U.S.C. 103 as being unpatentable over Ahn et al. (US 20230040524 A1, 06/28/2022, With priority to the filing date of 08/04/2020). Regarding claims 1-2 and 5, see 112b above. Ahn et al. generally disclose a modified polypeptide with attenuated activity of citrate synthase, a microorganism producing leucine comprising the modified polypeptide and a method for producing an L-amino acid using the microorganism (See entire document, Abstract). More specifically, Ahn et al. disclose a modified polypeptide having citrate synthase activity wherein the amino acid sequence of the modified polypeptide shares at least 80% but less than 100% sequence identity with the amino acid sequence of SEQ ID NO: 1 (Claim 1 of Ahn et al.). SEQ ID NO: 1 of Ahn et al. (Db) shares 99.2% sequence identity to instant SEQ ID NO: 8 (Qy) (the elected citrate synthase variant). Sequence alignment provided below. PNG media_image1.png 756 636 media_image1.png Greyscale The citrate synthase variant disclosed by Ahn et al. does not have a lysine at position 415. However, Ahn et al. further disclose the term variant refers to a polypeptide having at least one amino acid sequence different from the recited sequence by conservative substitutions and/or modifications such that functions or properties of the protein are retained (Paragraph [0017]) wherein conservative substitution means substituting an amino acid with another amino acid having similar structural or chemical properties (Paragraph [0018]). Ahn et al. specifically disclose histidine and lysine are examples of positively charged (basic) amino acids (Paragraph [0018]). Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have made a conservative substitution in the citrate synthase variant of Ahn et al. wherein a lysine was substituted for a histidine at any amino acid position, including position 415, motivated by the desire to create a modified variant because this is a known conservative substitution and conservative substitutions usually result in the function of the protein being retained as taught by Ahn et al. Regarding claim 3, see 112b above. Additionally, under the broadest reasonable interpretation, a polypeptide ‘represented by’ can be any sequence of peptides, not specifically the entire polypeptide sequence of SEQ ID NO: 3. As such, SEQ ID NO: 1 of Ahn et al. (Qy) contains a polypeptide sequence of instant SEQ ID NO: 3 (Db). Alignment provided below. PNG media_image2.png 134 606 media_image2.png Greyscale Regarding claim 4, see 112b above. Additionally, under the broadest reasonable interpretation, a polypeptide ‘represented by’ can be any sequence of peptides, not specifically the entire polypeptide sequence given in claim 4. As such, SEQ ID NO: 1 of Ahn et al. (Qy) comprises a polypeptide represented by instant SEQ ID NO: 51 (Db). Alignment provided below. PNG media_image3.png 234 588 media_image3.png Greyscale Regarding claim 6, Ahn et al. disclose a polynucleotide encoding the modified polypeptide of claim 1 (Claim 5 of Ahn et al.). Regarding claim 7, Ahn et al. disclose a microorganism producing an L-amino acid, comprising the modified polypeptide of claim 1 (Claim 7 of Ahn et al.). Regarding claims 8, 12 and 14, Ahn et al. disclose the L-amino acid is valine (Claim 13 of Ahn et al.). Regarding claims 9 and 15, Ahn et al. disclose the microorganism is Corynebacterium glutamicum (Claim 10 of Ahn et al.). Regarding claims 10 and 13, Ahn et al. disclose a method for producing an L-amino acid, comprising culturing a microorganism comprising the modified polypeptide of claim 1 (Claim 11 of Ahn et al.). Regarding claim 11, Ahn et al. disclose recovering an L-amino acid from the cultured medium or microorganism (Claim 12 of Ahn et al.). Claims 1-15 are rejected under 35 U.S.C. 103 as being unpatentable over Bathe et al. (US 20080014618 A1, 01/17/2008) (IDS Reference of 09/08/2023). Regarding claims 1-2 and 5, see 112b above. Bathe et al. generally disclose a citrate synthase and a method for producing L-amino acids (See entire document, Abstract). More specifically, Bathe et al. disclose an isolated polynucleotide, encoding a polypeptide comprising the amino acid sequence of SEQ ID NO: 2 wherein the polypeptide possesses citrate synthase activity (Claim 1 of Bathe et al.). SEQ ID NO: 2 of Bathe et al. (Db) shares 99.2% sequence identity to instant SEQ ID NO: 8 (Qy), the elected variant. Sequence alignment provided below. PNG media_image4.png 762 644 media_image4.png Greyscale The citrate synthase disclosed by Bathe et al. does not have a histidine at amino acid position 415. However, Bathe et al. further disclose the polypeptide comprises at least one conservative amino acid substitution which results in the citrate synthase activity remaining substantially unchanged (Claim 2 of Bathe et al.). Bathe et al. further disclose the specific conservative substitution of lysine for histidine as both are basic amino acids (Paragraph [0083]). Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have made a conservative amino acid substitution in the citrate synthase of Bathe et al. at any amino acid position, including position 415, of a lysine to a histidine motivated by the desire to create a variant that retained the activity of the protein because lysine to histidine is a known conservative amino acid substitution that would be expected to provide a citrate synthase with substantially unchanged activity. Regarding claim 3, see 112b above. Additionally, under the broadest reasonable interpretation, a polypeptide ‘represented by’ can be any sequence of peptides, not specifically the entire polypeptide sequence of SEQ ID NO: 3. It is noted SEQ ID NO: 3 is short sequence comprising amino acids 362-415 of SEQ ID NO: 8. Thus, SEQ ID NO: 2 of Bathe et al. comprises a polypeptide represented by the amino acid sequence of SEQ ID NO: 3. See alignment provided above. Regarding claim 4, see 112b above. Additionally, under the broadest reasonable interpretation, a polypeptide ‘represented by’ can be any sequence of peptides, not specifically the entire polypeptide sequence given in claim 4. It is noted SEQ ID NO: 51 is a 128 amino acid polypeptide comprising amino acids 290-415 of SEQ ID NO: 8 with 3 variable residues. Thus, SEQ ID NO: 2 of Bathe et al. comprises a polypeptide represented by the amino acid sequence of claim 4. See alignment provided above. Regarding claim 6, as discussed above, Bathe et al. disclose an isolated polynucleotide encoding the polypeptide of SEQ ID NO: 2 (Claim 1 of Bathe et al.). Regarding claims 7, 9 and 15, Bathe et al. disclose a recombinant bacterium of the genus Corynebacterium comprising SEQ ID NO:2 (Claim 16 of Bathe et al.) wherein the bacterium is Corynebacterium glutamicum (Claim 25 of Bathe et al.). Regarding claims 8, 10, 12-14, Bathe et al. disclose L-valine as the L-amino acid produced by culturing the bacterium of Claim 16 (Claims 26-27 of Bathe et al.). Regarding claim 11, Bathe et al. disclose the L-amino acid is collected (Claim 29 of Bathe et al.), reading on recovered. Double Patenting The nonstatutory double patenting rejection is based on a judicially created doctrine grounded in public policy (a policy reflected in the statute) so as to prevent the unjustified or improper timewise extension of the “right to exclude” granted by a patent and to prevent possible harassment by multiple assignees. A nonstatutory double patenting rejection is appropriate where the conflicting claims are not identical, but at least one examined application claim is not patentably distinct from the reference claim(s) because the examined application claim is either anticipated by, or would have been obvious over, the reference claim(s). See, e.g., In re Berg, 140 F.3d 1428, 46 USPQ2d 1226 (Fed. Cir. 1998); In re Goodman, 11 F.3d 1046, 29 USPQ2d 2010 (Fed. Cir. 1993); In re Longi, 759 F.2d 887, 225 USPQ 645 (Fed. Cir. 1985); In re Van Ornum, 686 F.2d 937, 214 USPQ 761 (CCPA 1982); In re Vogel, 422 F.2d 438, 164 USPQ 619 (CCPA 1970); In re Thorington, 418 F.2d 528, 163 USPQ 644 (CCPA 1969). A timely filed terminal disclaimer in compliance with 37 CFR 1.321(c) or 1.321(d) may be used to overcome an actual or provisional rejection based on nonstatutory double patenting provided the reference application or patent either is shown to be commonly owned with the examined application, or claims an invention made as a result of activities undertaken within the scope of a joint research agreement. See MPEP § 717.02 for applications subject to examination under the first inventor to file provisions of the AIA as explained in MPEP § 2159. See MPEP § 2146 et seq. for applications not subject to examination under the first inventor to file provisions of the AIA . A terminal disclaimer must be signed in compliance with 37 CFR 1.321(b). The filing of a terminal disclaimer by itself is not a complete reply to a nonstatutory double patenting (NSDP) rejection. A complete reply requires that the terminal disclaimer be accompanied by a reply requesting reconsideration of the prior Office action. Even where the NSDP rejection is provisional the reply must be complete. See MPEP § 804, subsection I.B.1. For a reply to a non-final Office action, see 37 CFR 1.111(a). For a reply to final Office action, see 37 CFR 1.113(c). A request for reconsideration while not provided for in 37 CFR 1.113(c) may be filed after final for consideration. See MPEP §§ 706.07(e) and 714.13. The USPTO Internet website contains terminal disclaimer forms which may be used. Please visit www.uspto.gov/patent/patents-forms. The actual filing date of the application in which the form is filed determines what form (e.g., PTO/SB/25, PTO/SB/26, PTO/AIA /25, or PTO/AIA /26) should be used. A web-based eTerminal Disclaimer may be filled out completely online using web-screens. An eTerminal Disclaimer that meets all requirements is auto-processed and approved immediately upon submission. For more information about eTerminal Disclaimers, refer to www.uspto.gov/patents/apply/applying-online/eterminal-disclaimer. Claims 1-15 are rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1-11 of U.S. Patent No. 12522808 B2. Although the claims at issue are not identical, they are not patentably distinct from each other because the claims of ‘808 are directed to a modified polypeptide having citrate synthase activity wherein the modified polypeptide has at least 80% but less than 100% sequence identity to SEQ ID NO: 1. SEQ ID NO:1 of ‘808 shares 99.6% sequence identity to instant SEQ ID NO:1. The claims of ‘808 further recite a polynucleotide sequence encoding the modified polypeptide, a vector comprising the polynucleotide, a microorganism comprising the modified polypeptide wherein the microorganism is of the genus Corynebacterium. Thus, the claims of ‘808 anticipate the instant claims. Claims 1-5 and 7-15 are provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1-20 of copending Application No. 18/279,519 (reference application). Although the claims at issue are not identical, they are not patentably distinct from each other because the claims of ‘519 are directed to a citrate synthase variant wherein the amino acid at the position corresponding to position 415 of the polypeptide of SEQ ID NO: 1 is substituted with histidine and the variant is at least 80% identical to SEQ ID NO: 1. SEQ ID NO:1 of ‘519 shares 99.6% sequence identity to instant SEQ ID NO: 1. The dependent claims of ‘519 are drawn to a microorganism comprising the citrate synthase variant and culturing the microorganism to produce L-amino acids. This is a provisional nonstatutory double patenting rejection because the patentably indistinct claims have not in fact been patented. Claims 1-15 are provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1-17 of copending Application No. 18/280,575 (reference application). Although the claims at issue are not identical, they are not patentably distinct from each other because the claims of ‘575 are directed to a citrate synthase that shares 80% sequence identity to SEQ ID NO: 1. SEQ ID NO:1 of ‘575 shares 100% sequence identity to instant SEQ ID NO: 1. The dependent claims of ‘575 are drawn to a microorganism comprising the citrate synthase variant and culturing the microorganism to produce L-amino acids. This is a provisional nonstatutory double patenting rejection because the patentably indistinct claims have not in fact been patented. Conclusion Claims 1-15 are rejected. No claims are allowed. Any inquiry concerning this communication or earlier communications from the examiner should be directed to ASHLEY T WHITE whose telephone number is (571)272-0683. The examiner can normally be reached Monday - Friday 8:30 - 5:00 EST. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Sharmila Landau can be reached at (571)272-0614. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /A.T.W./Examiner, Art Unit 1653 /SHARMILA G LANDAU/Supervisory Patent Examiner, Art Unit 1653
Read full office action

Prosecution Timeline

Sep 08, 2023
Application Filed
Mar 12, 2026
Non-Final Rejection — §103, §112, §DP (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

1-2
Expected OA Rounds
36%
Grant Probability
99%
With Interview (+77.8%)
3y 5m
Median Time to Grant
Low
PTA Risk
Based on 11 resolved cases by this examiner. Grant probability derived from career allow rate.

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